Delayed Diagnosis of Ectopic Cushing Syndrome

Posted on April 3, 2024 by MaryO

Abstract

Here, we present the case of a 40-year-old man in whom the diagnosis of ectopic adrenocorticotropin (ACTH) syndrome went unrecognized despite evaluation by multiple providers until it was ultimately suspected by a nephrologist evaluating the patient for edema and weight gain. On urgent referral to endocrinology, screening for hypercortisolism was positive by both low-dose overnight dexamethasone suppression testing and 24-hour urinary free cortisol measurement. Plasma ACTH values confirmed ACTH-dependent Cushing syndrome. High-dose dexamethasone suppression testing was suggestive of ectopic ACTH syndrome. Inferior petrosal sinus sampling demonstrated no central-to-peripheral gradient, and 68Ga-DOTATATE scanning revealed an avid 1.2-cm left lung lesion. The suspected source of ectopic ACTH was resected and confirmed by histopathology, resulting in surgical cure. While many patients with Cushing syndrome have a delayed diagnosis, this case highlights the critical need to increase awareness of the signs and symptoms of hypercortisolism and to improve the understanding of appropriate screening tests among nonendocrine providers.

Introduction

Even in the face of overt clinical signs and symptoms of hypercortisolism, diagnosing Cushing syndrome requires a high index of suspicion, and people with hypercortisolism experience a long road to diagnosis. In a recent meta-analysis including more than 5000 patients with Cushing syndrome, the mean time to diagnosis in all Cushing syndrome, including Cushing disease and ectopic adrenocorticotropin (ACTH) syndrome, was 34 months (1). Reasons for delayed diagnosis are multifactorial, including the nonspecific nature of subjective symptoms and objective clinical signs, as well as notorious challenges in the interpretation of diagnostic testing. Furthermore, the health care system’s increasingly organ-specific referral patterns obfuscate multisystem disorders. Improving the recognition of and decreasing time to diagnosis in Cushing syndrome are critical factors in reducing morbidity and mortality.

Here, we present the case of a patient who, despite classic signs of Cushing syndrome as well as progressive physical and mental decline, remained undiagnosed for more than 3 years while undergoing repeated evaluation by primary care and subspecialty providers. The case (1) highlights the lack of awareness of Cushing syndrome as a potential unifying diagnosis for multiorgan system problems; (2) underscores the necessity of continued education on the signs and symptoms of hypercortisolism, appropriate screening for hypercortisolism, and early referral to endocrinology; and (3) provides an opportunity for systemic change in clinical laboratory practice that could help improve recognition of pathologic hypercortisolism.

Case Presentation

In August 2018, a previously healthy 40-year-old man with ongoing tobacco use established care with a primary care provider complaining that he had been ill since the birth of his son 13 months prior. He described insomnia, headaches, submandibular swelling, soreness in his axillary and inguinal regions, and right-sided chest discomfort (Fig. 1). Previously, he had been diagnosed with sinusitis, tonsillitis, and allergies, which had been treated with a combination of antibiotics, antihistamines, and intranasal glucocorticoids. He was referred to otolaryngology where, in the absence of cervical lymphadenopathy, he was diagnosed with sternocleidomastoid pain with recommendations to manage conservatively with stretching and massage. A chest x-ray demonstrated a left apical lung nodule. Symptoms continued unabated throughout 2019, now with a cough. Repeat chest x-ray demonstrated opacities lateral to the left hilum that were attributed to vascular structures.

 

Figure 1.

Timeline of development of subjective symptoms and objective clinical findings preceding diagnosis and surgical cure of ectopic Cushing syndrome.

In May 2020, increasingly frustrated with escalating symptoms, the patient transitioned care to a second primary care provider and was diagnosed with hypertension. He complained of chronic daily headaches that prompted brain imaging with magnetic resonance imaging (MRI), which noted findings consistent with left maxillary silent sinus syndrome. He was sent back to otolaryngology, which elected to proceed with sinus surgery. During this time, he suffered a fibular fracture for which he was evaluated by orthopedic surgery. In the second half of 2020, he was seen by neurology to evaluate his chronic headaches and paresthesias with electromyography demonstrating a left ulnar mononeuropathy consistent with cubital tunnel syndrome. His primary care provider diagnosed him with fibromyalgia for which he started physical therapy, and he was referred to a pain clinic for cognitive behavioral therapy. Unfortunately his wife, dealing with her husband’s increasing cognitive and personality changes including irritability and aggression, filed for divorce.

At the end of 2020, the patient developed bilateral lower extremity edema and was prescribed hydrochlorothiazide, subsequently developing hypokalemia attributed to diuretic use. With worsening bilateral lower extremity edema and new dyspnea on exertion, he was evaluated for heart failure with an echocardiogram, which was unremarkable. Over the next several months, he gained approximately 35 pounds (∼16 kg). It was in the setting of weight gain that he was first evaluated for hypercortisolism with random serum cortisol of 22.8 mcg/dL (629 nmol/L) and 45.6 mcg/dL (1258 nmol/L) in the late morning and mid-day, respectively. No reference range was provided for the times of day at which these laboratory values were drawn. Although these serum cortisol values were above provided reference ranges for other times of day, they were not flagged as abnormal by in-house laboratory convention, and they were overlooked. The search for other etiologies of his symptoms continued.

In early 2021, diuretic therapy and potassium supplementation were escalated for anasarca. He developed lower extremity cellulitis and received multiple courses of antibiotics. Skin biopsy performed by dermatology demonstrated disseminated Mycobacterium and later Serratia (2), prompting referral to infectious disease for management. Additional subspecialty referrals included rheumatology (polyarthralgia) and gastroenterology (mildly elevated alanine transaminase with planned liver biopsy). In July 2021, he was evaluated for edema by nephrology, where the constellation of subjective symptoms and objective data including hypertension, central weight gain, abdominal striae, fracture, edema, easy bruising, medication-induced hypokalemia, atypical infections, and high afternoon serum cortisol were noted, and the diagnosis of Cushing syndrome was strongly suspected. Emergent referral to endocrinology was placed.

Diagnostic Assessment

At his first clinic visit with endocrinology in June 2021, the patient’s blood pressure was well-controlled on benazepril. Following weight gain of 61 pounds (∼28 kg) in the preceding 2 years, body mass index was 33. Physical examination demonstrated an ill-appearing gentleman with dramatic changes when compared to prior pictures (Fig. 2), including moon facies, dorsocervical fat pad, violaceous abdominal striae, weeping lower extremity skin infections, an inability to stand without assistance from upper extremities, and depressed mood with tangential thought processes.

 

Figure 2.

Photographic representation of physical changes during the years leading up to diagnosis of ectopic Cushing syndrome in June 2021 and after surgical resection of culprit lesion.

Diagnostic workup for hypercortisolism included a morning cortisol of 33.4 mcg/dL (922 nmol/L) (normal reference range, 4.5-22.7 mcg/dL) and ACTH of 156 pg/mL (34 pmol/L) (normal reference range, 7.2-63 pg/mL) following bedtime administration of 1-mg dexamethasone, and 24-hour urine free cortisol of 267 mcg/24 hours (737 nmol/24 hours) (normal reference range, 3.5-45 mcg/24 hours). Morning serum cortisol and plasma ACTH following bedtime administration of 8-mg dexamethasone were 27.9 mcg/dL (770 nmol/L) and 98 pg/mL (22 pmol/L), respectively. Given concern for potential decompensation, he was hospitalized for expedited work-up. Brain MRI did not demonstrate a pituitary lesion (Fig. 3), and inferior petrosal sinus sampling under desmopressin stimulation showed no central-to-peripheral gradient (Table 1). He underwent a positron emission tomography–computed tomography 68Ga-DOTATATE scan that demonstrated a 1.2-cm left pulmonary nodule with radiotracer uptake (Fig. 4).

 

Figure 3.

A, Precontrast and B, postcontrast T1-weighted sagittal magnetic resonance imaging of the sella. Images were affected by significant motion degradation, precluding clear visualization of the pituitary gland on coronal imaging.

 

Figure 4.

68Ga-DOTATATE imaging. A, Coronal and B, axial views of the chest after administration of radiopharmaceutical. Arrow in both panels indicates DOTATATE-avid 1.2-cm left lung lesion.

 
Table 1.

Bilateral petrosal sinus and peripheral adrenocorticotropin levels preintravenous and postintravenous injection of desmopressin acetate 10 mcg

Time post DDAVP, min Left petrosal ACTH Left petrosal:peripheral ACTH Right petrosal ACTH Right petrosal:peripheral ACTH Peripheral ACTH Left:right petrosal ACTH
0 172 pg/mL
(37.9 pmol/L)		 1.1 173 pg/mL
(38.1 pmol/L)		 1.2 150 pg/mL
(33.0 pmol/L)		 1.0
3 288 pg/mL
(63.4 pmol/L)		 1.8 292 pg/mL
(64.3 pmol/L)		 1.8 162 pg/mL
(35.7 pmol/L)		 1.0
5 348 pg/mL
(76.6 pmol/L)		 1.8 341 pg/mL
(75.1 pmol/L)		 1.8 191 pg/mL
(42.1 pmol/L)		 1.0
10 367 pg/mL
(80.8 pmol/L)		 1.3 375 pg/mL
(82.6 pmol/L)		 1.3 278 pg/mL
(61.2 pmol/L)		 1.0

Abbreviations: ACTH, adrenocorticotropin; DDAVP, desmopressin acetate.

Treatment

The patient was started on ketoconazole 200 mg daily for medical management of ectopic ACTH-induced hypercortisolism while awaiting definitive surgical treatment. Within a month of initial endocrinology evaluation, he underwent thoracoscopic left upper lobe wedge resection with intraoperative frozen histopathology section consistent with a well-differentiated neuroendocrine tumor and final pathology consistent with a well-differentiated neuroendocrine tumor. Staining for ACTH was positive (Fig. 5). Postoperative day 1 morning cortisol was 1.4 mcg/dL (39 nmol/L) (normal reference range, 4.5-22.7 mcg/dL). He was started on glucocorticoid replacement with hydrocortisone and was discharged from his surgical admission on hydrocortisone 40 mg in the morning and 20 mg in the afternoon.

 

Figure 5.

Lung tumor histopathology. A, The tumor was epicentered around a large airway (asterisk) and showed usual architecture for carcinoid tumor. B, The tumor cells had monomorphic nuclei with a neuroendocrine chromatin pattern, variably granulated cytoplasm, and a delicate background vascular network. By immunohistochemistry, the tumor cells were strongly positive for C, synaptophysin; D, CAM5.2; and E, adrenocorticotropin. F, Ki-67 proliferative index was extremely low (<1%).

Outcome and Follow-up

Approximately 12 days after discharge, the patient was briefly readmitted from the skilled nursing facility where he was receiving rehabilitation due to a syncopal event attributed to hypovolemia. This was felt to be secondary to poor oral intake in the setting of both antihypertensive and diuretic medications as well as an episode of emesis earlier in the morning precluding absorption of his morning hydrocortisone dose. Shortly after this overnight admission, he was discharged from his skilled nursing facility to home. In the first month after surgery, he lost approximately 30 pounds (∼14 kg) and had improvements in sleep and mood.

Eight months after surgery, hydrocortisone was weaned to 10 mg daily. Cosyntropin stimulation testing holding the morning dose showed 1 hour cortisol 21.5 mcg/dL (593 nmol/L). Hydrocortisone was subsequently discontinued. In June 2022, 1 year following surgery, 3 sequential midnight salivary cortisol tests were undetectable. At his last visit with endocrinology in June 2023, he felt well apart from ongoing neuropathic pain in his feet and continued but improved mood disturbance. Though his health has improved dramatically, he continues to attribute his divorce and substantial life disruption to his undiagnosed hypercortisolism.

Discussion

Endogenous neoplastic hypercortisolism encompasses a clinical spectrum from subclinical disease, as is common in benign adrenal cortical adenomas, to overt Cushing syndrome of adrenal, pituitary, and ectopic origin presenting with dramatic clinical manifestations (3) and long-term implications for morbidity and mortality (4). Even in severe cases, a substantial delay in diagnosis is common. In this case, despite marked hypercortisolism secondary to ectopic ACTH syndrome, the patient’s time from first symptoms to diagnosis was more than 3 years, far in excess of the typical time to diagnosis in this subtype, noted to be 14 months in 1 study (1).

He initially described a constellation of somatic symptoms including subjective neck swelling, axillary and inguinal soreness, chest discomfort, and paresthesias, and during the year preceding diagnosis, he developed hypertension, fibular fracture, mood changes, weight gain, peripheral edema, hypokalemia, unusual infections, and abdominal striae. Each of these symptoms in isolation is a common presentation in the primary care setting, therefore the challenge arises in distinguishing common, singular causes from rare, unifying etiologies, especially given the present epidemics of diabetes, obesity, and associated cardiometabolic abnormalities. By Endocrine Society guidelines, the best discriminatory features of Cushing syndrome in the adult population are facial plethora, proximal muscle weakness, abdominal striae, and easy bruising (5). Furthermore, Endocrine Society guidelines suggest evaluating for Cushing disease when consistent clinical features are present at a younger-than-expected age or when these features accumulate and progress, as was the case with our patient (5).

However, even when the diagnosis is considered, the complexities of the hypothalamic-pituitary-adrenal axis make selection and interpretation of screening tests challenging outside the endocrinology clinic. We suspect that in most such situations, a random serum cortisol measurement is far more likely to be ordered than a validated screening test, such as dexamethasone suppression testing, urine free cortisol, and late-night salivary cortisol per Endocrine Society guidelines (5). Although random serum cortisol values are not considered a screening test for Cushing syndrome, elevated values can provide a clue to the diagnosis in the right clinical setting. In this case, 2 mid-day serum cortisols were, by in-house laboratory convention, not flagged as abnormal despite the fact that they were above the upper limit of provided reference ranges. We suspect that the lack of electronic medical record flagging of serum cortisol values contributed to these values being incorrectly interpreted as ruling out the diagnosis.

Cushing syndrome remains among the most evasive and difficult diagnoses in medicine due to the doubly difficult task of considering the disorder in the face of often protean signs and symptoms and subsequently conducting and interpreting screening tests. The challenges this presents for the nonendocrinologist have recently been recognized by a group in the United Kingdom after a similarly overlooked case (6). We believe that our case serves as a vivid illustration of the diagnostic hurdles the clinician faces and as a cautionary tale with regard to the potential downstream effects of a delay in diagnosis. Standardization of clinical laboratory practices in flagging abnormal cortisol values is one such intervention that may aid the busy clinician in more efficiently recognizing laboratory results suggestive of this diagnosis. While false-positive case detection is a significant downside to this approach, given the potential harm in delayed or missed diagnosis, the potential benefits may outweigh the risks.

Learning Points

  • People with Cushing syndrome frequently experience a prolonged time to diagnosis, in part due to lack of recognition in the primary care and nonendocrine subspecialty settings of the constellation of clinical findings consistent with hypercortisolism.
  • Endocrine Society guidelines recommend against random serum cortisol as initial testing for Cushing syndrome in favor of dexamethasone suppression testing, urine free cortisol, and late-night salivary cortisol.
  • Increased awareness of Cushing syndrome by primary care providers and specialists in other fields could be an important and impactful mechanism to shorten the duration of symptom duration in the absence of diagnosis and hasten cure where cure is achievable.
  • We suggest clinical laboratories consider standardizing flagging abnormal cortisol values to draw attention to ordering providers and perhaps lower the threshold for endocrinology referral if there is any uncertainty in interpretation, especially in the context of patients with persistent symptoms and elusive diagnoses.

Acknowledgments

We are grateful to the patient for allowing us to present his difficult case to the community with the hopes of improving time to diagnosis for patients with hypercortisolism.

Contributors

All authors made individual contributions to authorship. J.M.E., E.M.Z., and K.R.K. were involved in the diagnosis and management of this patient. B.C.M., J.M.E., E.M.Z., and K.R.K. were involved in manuscript submission. S.M.J. performed and analyzed histopathology and prepared the figure for submission. All authors reviewed and approved the final draft.

Funding

No public or commercial funding.

Disclosures

J.M.E. was on the editorial board of JCEM Case Reports at the time of initial submission.

Informed Patient Consent for Publication

Signed informed consent obtained directly from the patient.

Data Availability Statement

Data sharing is not applicable to this article as no data sets were generated or analyzed during the current study.

References

1

Rubinstein
G

,

Osswald
A

,

Hoster
E

, et al.

Time to diagnosis in Cushing’s syndrome: a meta-analysis based on 5367 patients

.

J Clin Endocrinol Metab

.

2020

;

105

(

3

):

dgz136

.

2

Park
MA

,

Gaghan
LJ

,

Googe
PB

,

Klein
KR

,

Mervak
JE

.

Disseminated cutaneous Mycobacterium chelonae infection as a presenting sign of ectopic adrenocorticotropic hormone syndrome

.

JAAD Case Rep

.

2021

;

18

:

79

‐

81

.

3

Reincke
M

,

Fleseriu
M

.

Cushing syndrome: a review

.

JAMA

.

2023

;

330

(

2

):

170

‐

181

.

4

Puglisi
S

,

Perini
AME

,

Botto
C

,

Oliva
F

,

Terzolo
M

.

Long-term consequences of Cushing’s syndrome: a systematic literature review

.

J Clin Endocrinol Metab

. 2024;

109

(

3

):

e901

‐

e909

.

5

Nieman
LK

,

Biller
BMK

,

Findling
JW

, et al.

The diagnosis of Cushing’s syndrome: an Endocrine Society clinical practice guideline

.

J Clin Endocrinol Metab

.

2008

;

93

(

5

):

1526

‐

1540

.

6

Scoffings
K

,

Morris
D

,

Pullen
A

,

Temple
S

,

Trigell
A

,

Gurnell
M

.

Recognising and diagnosing Cushing’s syndrome in primary care: challenging but not impossible

.

Br J Gen Pract

.

2022

;

72

(

721

):

399

‐

401

.

Abbreviations

 

  • ACTH

    adrenocorticotropin

  • MRI

    magnetic resonance imaging

© The Author(s) 2024. Published by Oxford University Press on behalf of the Endocrine Society.
This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs licence (https://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial reproduction and distribution of the work, in any medium, provided the original work is not altered or transformed in any way, and that the work is properly cited. For commercial re-use, please contact journals.permissions@oup.com

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Day 1: Cushing’s Awareness Challenge

Posted on April 1, 2024 by MaryO

April is always Cushing’s Awareness Challenge month because Dr. Harvey Cushing was born on April 8th, 1869.

30-posts

Thanks to Robin for this wonderful past logo!  I’ve participated in these 30 days for Cushing’s Awareness several times so I’m not quite sure what is left to say this year but I always want to get the word out when I can.

As I see it, there have been some strides the diagnosis or treatment of Cushing’s since last year.  More drug companies are getting involved, more doctors seem to be willing to test, a bit more awareness, maybe.

April Fool's Day

How fitting that this challenge should begin on April Fool’s Day.  So much of Cushing’s  Syndrome/Disease makes us Cushies seem like we’re the April Fool.  Maybe, just maybe, it’s the doctors who are the April Fools…

Doctors tell us Cushing’s is too rare – you couldn’t possibly have it.  April Fools!

All you have to do is exercise and diet.  You’ll feel better.  April Fools!

Those bruises on your legs?  You’re just clumsy. April Fools!

Sorry you’re growing all that hair on your chin.  That happens as you age, you know.  April Fools!

Did you say you sleep all day?  You’re just lazy.  If you exercised more, you’d have more energy. April Fools!

You don’t have stretch marks.  April Fools!

You have stretch marks but they are the wrong [color/length/direction] April Fools!

The hump on the back of your neck is from your poor posture. April Fools!

Your MRI didn’t show a tumor.  You couldn’t have Cushing’s. April Fools!

This is all in your mind.  Take this prescription for antidepressants and go home.  April Fools!

If you have this one surgery, your life will get back to normal within a few months. April Fools!

What?  You had transsphenoidal surgery for Cushing’s?  You wasted your time and money. April Fools!

I am the doctor.  I know everything.  Do not try to find out any information online. You could not have Cushing’s.  It’s too rare…  April FOOL!

All this reminds me of a wonderful video a message board member posted a while ago:

So now – who is the April Fool?  It wasn’t me.  Don’t let it be you, either!

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Epicardial and Pericoronary Adipose Tissue and Coronary Plaque Burden in Patients with Cushing’s Syndrome

Posted on March 18, 2024 by MaryO

Abstract

Purpose

To assess coronary inflammation by measuring the volume and density of the epicardial adipose tissue (EAT), perivascular fat attenuation index (FAI) and coronary plaque burden in patients with Cushing’s syndrome (CS) based on coronary computed tomography angiography (CCTA).

Methods

This study included 29 patients with CS and 58 matched patients without CS who underwent CCTA. The EAT volume, EAT density, FAI and coronary plaque burden were measured. The high-risk plaque (HRP) was also evaluated. CS duration from diagnosis, 24-h urinary free cortisol (UFC), and abdominal visceral adipose tissue volume (VAT) of CS patients were recorded.

Results

The CS group had higher EAT volume (146.9 [115.4, 184.2] vs. 119.6 [69.0, 147.1] mL, P = 0.006), lower EAT density (− 78.79 ± 5.89 vs. − 75.98 ± 6.03 HU, P = 0.042), lower FAI (− 84.0 ± 8.92 vs. − 79.40 ± 10.04 HU, P = 0.038), higher total plaque volume (88.81 [36.26, 522.5] vs. 44.45 [0, 198.16] mL, P = 0.010) and more HRP plaques (7.3% vs. 1.8%, P = 0.026) than the controls. The multivariate analysis suggested that CS itself (β [95% CI], 29.233 [10.436, 48.03], P = 0.014), CS duration (β [95% CI], 0.176 [0.185, 4.242], P = 0.033), and UFC (β [95% CI], 0.197 [1.803, 19.719], P = 0.019) were strongly associated with EAT volume but not EAT density, and EAT volume (β [95% CI] − 0.037[− 0.058, − 0.016], P = 0.001) not CS was strongly associated with EAT density. EAT volume, FAI and plaque burden increased (all P < 0.05) in 6 CS patients with follow-up CCTA. The EAT volume had a moderate correlation with abdominal VAT volume (r = 0.526, P = 0.008) in CS patients.

Conclusions

Patients with CS have higher EAT volume and coronary plaque burden but less inflammation as detected by EAT density and FAI. The EAT density is associated with EAT volume but not CS itself.

From https://link.springer.com/article/10.1007/s40618-023-02295-x

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Interpetrosal Sphingosine-1-Phosphate Ratio Predicting Cushing’s Disease Tumor Laterality and Remission After Surgery

Posted on November 20, 2023 by MaryO

Background: Cushing’s disease (CD) poses significant challenges in its treatment due to the lack of reliable biomarkers for predicting tumor localization or postoperative clinical outcomes. Sphingosine-1-phosphate (S1P) has been shown to increase cortisol biosynthesis and is regulated by adrenocorticotropic hormone (ACTH).

Methods: We employed bilateral inferior petrosal sinus sampling (BIPSS), which is considered the gold standard for diagnosing pituitary sources of CD, to obtain blood samples and explore the clinical predictive value of the S1P concentration ratio in determining tumor laterality and postoperative remission. We evaluated 50 samples from 25 patients who underwent BIPSS to measure S1P levels in the inferior petrosal sinuses bilaterally.

Results: Serum S1P levels in patients with CD were significantly higher on the adenoma side of the inferior petrosal sinus than on the nonadenoma side (397.7 ± 15.4 vs. 261.9 ± 14.88; P < 0.05). The accuracy of diagnosing tumor laterality with the interpetrosal S1P and ACTH ratios and the combination of the two was 64%, 56% and 73%, respectively. The receiver operating characteristic curve analysis revealed that the combination of interpetrosal S1P and ACTH ratios, as a predictor of tumor laterality, exhibited a sensitivity of 81.82% and a specificity of 75%, with an area under the curve value of 84.09%. Moreover, we observed that a high interpetrosal S1P ratio was associated with nonremission after surgery. Correlation analyses demonstrated that the interpetrosal S1P ratio was associated with preoperative follicle-stimulating hormone (FSH), luteinizing hormone (LH), and postoperative ACTH 8 am levels (P < 0.05).

Conclusion: Our study demonstrated a significant association between the interpetrosal S1P ratio and tumor laterality, as well as postoperative remission in CD, suggesting that the interpetrosal S1P ratio could serve as a valuable biomarker in clinical practice.

1 Introduction

Cushing’s disease (CD), also known as adrenocorticotropic hormone (ACTH)-secreting pituitary adenoma, arises from the pituitary corticotroph cells and induces endogenous hypercortisolism by stimulating the adrenal glands to produce excessive amount of cortisol (1). Patients with CD typically exhibit symptoms of hypercortisolism, such as hypertension, diabetes, purplish skin striae, mental disturbances, hyposexuality, hirsutism, menstrual disorders, acne, fatigue, obesity, and osteoporosis (1). The overall mortality of patients with CD is twice that of the general population, and if left untreated, hypercortisolism resulting from CD increases this rate to approximately four times the expected value (2–4). Transsphenoidal surgery continues to be the primary treatment for CD (5). However, previous studies reported variable remission rates, ranging from 45% to 95% (6–8). Long-term follow-up data have revealed recurrence in 3–66% of patients who had initially achieved complete remission (9, 10). The rate of surgical remission in CD can be influenced by various factors, including the size and location of the tumor, expertise of the neurosurgeon, and criteria used for assessing remission (11). Preoperative clinical variables, such as age, gender, disease duration, and severity of clinical signs and symptoms, cannot reliably identify patients at a higher risk of nonremission (12, 13). Therefore, predicting postsurgical remission in CD remains a challenging goal.

Accumulating evidence has shown that sphingosine-1-phosphate (S1P), an intracellular pleiotropic bioactive sphingolipid metabolite synthesized by sphingosine kinase 1 (SPHK1), plays a pivotal role in diverse endocrine disorders (14–16). Overexpression of SPHK1 promotes the progression of multiple neuroendocrine tumors (17, 18). ACTH can rapidly activate sphingolipid metabolism, causing an increase in S1P secretion in the adrenal cortex (19). Furthermore, the activation of S1P signaling in H295R cells, a human adrenocortical tumor cell line, has been suggested to induce increased transcription of hormone-sensitive lipase and steroidogenic acute regulatory protein, ultimately elevating cortisol production (20). Recently, surgical removal of ACTH-secreting adenoma has been reported to cause a decline in sphingomyelin levels (21). However, whether they have a similar role in the pituitary gland remains to be investigated.

Bilateral inferior petrosal sinus sampling (BIPSS) is a highly effective procedure for diagnosing pituitary sources of ACTH in CD (22, 23). Contemporaneous differences in ACTH concentration during venous sampling between the two sides of the adenoma can predict the location of the adenoma within the pituitary (on the side of the gland with a microadenoma) and may guide surgical treatment in cases with inconclusive magnetic resonance imaging findings. Previous studies demonstrated that an ACTH gradient of ≥1.4 between the inferior petrosal sinuses can indicate microadenoma lateralization in patients with CD (24–26). However, the correct lateralization only occurs in 57–68% of all cases (27–29).

Therefore, we analyzed the clinical behavior of a well-characterized cohort of patients with CD who underwent BIPSS before surgery. We measured the difference in the concentration of S1P in bilateral petrosal sinus blood samples and explored the clinical predictive value of the S1P concentration ratio in determining tumor laterality and postoperative remission.

2 Materials and methods

2.1 Patients and study design

This study was conducted at a tertiary center, involving a cohort of 25 patients diagnosed with CD who had undergone BIPSS and surgery, with a minimum follow-up duration of 2 years. Comprehensive chart reviews were conducted to collect data on demographics, clinical characteristics, pituitary imaging findings, tumor pathology, and biochemical tests.

The criteria used for diagnosing CD encompassed the presence of characteristic signs and symptoms of hypercortisolism, along with biochemical evaluation of two urinary free cortisol measurements exceeding the normal range for the respective assay, serum cortisol level >1.8 μg/dL (50 nmol/L) after an overnight 1-mg dexamethasone suppression test, and two late-night salivary cortisol measurements exceeding the normal range for the respective assay (30). A diagnosis of Cushing’s syndrome was established if the patient had positive test results for at least two of the three aforementioned tests. Adrenal insufficiency was diagnosed if patients exhibited symptoms or signs of adrenal insufficiency or if serum cortisol levels were ≤3 μg/dL, even in the absence of clinical signs or symptoms. Remission was defined as normalization of the levels of 24-h urinary free cortisol, late-night salivary cortisol, and overnight 1-mg dexamethasone suppression test in patients without concurrent central adrenal insufficiency after surgery (31).

2.2 Patients and tissue/serum samples

Surgical specimens of CD-affected tissues were collected from Xiangya Hospital, Central South University. Three normal pituitary tissues were obtained from cadaveric organ donors without any history of endocrine disease (Central South University). A total of 25 CD tissue samples were obtained for immunohistochemistry analysis. This study was conducted in compliance with the Helsinki Declaration and was ethically approved by the Xiangya Hospital Ethics Committee, Xiangya Hospital (Changsha, China). Tumor samples and corresponding clinical materials were obtained with written consent from all patients.

2.3 BIPSS

After obtaining informed consent, BIPSS was performed using standard techniques described in previous studies (32, 33). Briefly, the patient’s head was immobilized to ensure midline positioning and prevent any potential bias towards asymmetric pituitary drainage by the petrosal sinuses. After placing peripheral catheters and cannulating both inferior petrosal sinuses, blood samples were collected at baseline and at 3, 5, 10, and 15 min following intravenous administration of DDAVP, which stimulates pituitary production of ACTH. Additional samples for experimental purposes were collected immediately following the 15-min sample collection to avoid interference with the patient’s diagnostic study.

2.4 Measurement of baseline plasma S1P concentration

Blood samples were obtained from both petrosal sinuses and were centrifuged to remove cellular components. Samples that exhibited hemolysis or coagulation were excluded from the study. Plasma samples were stored at −80°C. The S1P levels in plasma were analyzed using a S1P competitive ELISA kit (Echelon Biosciences, Salt Lake City, UT) according to the manufacturer’s instructions (34).

2.5 Immunofluorescence staining

The pituitary tissues were post-fixed and dehydrated with alcohol as follows: 70% for 24 h, 80% for 3 h, 90% for 4 h, 95% for 3 h, and finally in absolute alcohol for 2 h. Tissue slices with a 5-μm thickness were cut using a microtome (Thermo Fisher Scientific), blocked with 3% BSA, and then treated with primary antibodies to SPHK1 (CST, #3297) and ACTH (Proteintech, CL488-66358). Subsequently, the tissue slides were incubated with Alexa Fluor 488-conjugated anti-rabbit (Invitrogen, A21206, 1:200) or Alexa Fluor 555-conjugated anti-rabbit (Invitrogen, A21428, 1:200) secondary antibodies. Specimens were visualized and imaged using a fluorescence microscope.

2.6 Statistical analysis

The Mann–Whitney U test was used to assess the clinical–molecular associations in adenoma samples, whereas the chi-square test was used to compare categorical data. The Kruskal–Wallis analysis and ANOVA were conducted for multiple comparisons. Statistical analyses were conducted using SPSS v20 and GraphPad Prism version 7. All results were presented in graphs and tables as median ± interquartile range. The distribution of each parameter was presented as the minimum–maximum range. Parametric or nonparametric statistical tests were applied, as appropriate, after testing for normality. The receiver operating characteristic curve was used to determine the cut-off value for predicting tumor laterality. Pearson correlation analyses was used to examine the correlations between variables. Proportions were expressed as percentages, and significance was defined as P < 0.05.

3 Results

3.1 Clinical characteristics of remission and nonremission in patients with CD

This study included 25 patients with CD who underwent BIPSS before surgery (Figure 1). Among them, 12 patients had microadenomas, whereas the remaining 13 had inconclusive magnetic resonance imaging findings; clinicopathological data are summarized in Supplementary Table 1. Table 1 displays the demographics of patients who achieved remission (n = 16) and those who did not (n = 9). No significant differences were observed in terms of sex, age at diagnosis, or radiological variables between patients who achieved and those who did not achieve remission (P > 0.05). Patients who achieved remission exhibited a higher prevalence of emotional lability (P < 0.05). However, no significant differences were observed in other parameters (P > 0.05).

Figure 1
www.frontiersin.orgFigure 1 Flowchart of the screening process employed to select eligible participants for the study.

Table 1
www.frontiersin.orgTable 1 Baseline clinical features of patients with pituitary tumors secreting adrenocorticotropin.

Several recent studies have established morning cortisol level measured on postoperative day 1 (POD1) as a predictive biomarker for long-term remission of CD (35, 36). For biochemical features, patients who did not achieve remission exhibited higher serum cortisol (19.16 ± 5.55 vs. 5.95 ± 1.42; P = 0.014) and median serum (8 am) ACTH (10.26 ± 8.24 vs. 5.15 ± 3.68; P = 0.042) levels on POD1. No significant differences were observed in the preoperative baseline 4 pm serum cortisol levels, preoperative baseline 0 am serum cortisol levels, preoperative 8 pm ACTH levels, 4 pm ACTH levels, and 0 am ACTH levels (P > 0.05) (Table 2). In addition preoperative FT3, FT4, TSH, GH, FSH, LH, and PRL levels were comparable in patients with and without remission.

Table 2
www.frontiersin.orgTable 2 Baseline clinical and biochemical features of patients with pituitary tumors secreting adrenocorticotropin.

3.2 Overexpression of SPHK1 and higher concentrations of serum S1P on the tumor side in patients with CD

Prior studies have demonstrated that ACTH acutely activates SPHK1 to increase S1P concentrations (19). Upregulation of SPHK1 is associated with poor prognosis in endocrine-related cancer (17, 18, 21). To investigate the role of SPHK1 in CD, we performed a heatmap analysis of key genes involved in phospholipid metabolism and signaling pathways in CD adenomas and surrounding normal tissues using the GEO dataset (GEO208107). This analysis revealed the activation of crucial genes involved in phospholipid metabolism and signaling pathways in ACTH-secreting pituitary adenomas (Supplementary Figure 1). Subsequently, we compared the association between pituitary SPHK1 expression and proopiomelanocortin, corticotropin-releasing hormone, corticotropin releasing hormone receptor 1, and corticotropin releasing hormone receptor 2 in pituitary tumor tissues and identified a positive correlation between SPHK1 and ACTH tumor-related genes in the TNM plot database (Supplementary Figure 2). To investigate the potential role of SPHK1 in CD, we compared the expression values of SPHK1 in the normal pituitary tissues and those obtained from patients with CD in the remission/nonremission groups. Immunofluorescence staining (Figures 2A, B; Supplementary Figure 3) revealed an increased number of double-positive cells for SPHK1 and ACTH in CD-affected pituitary tissues than those in the normal pituitary tissues. Furthermore, the proportion of double-positive cells for SPHK1 and ACTH was significantly higher in the nonremission CD adenomas tissues than that in the remission CD adenomas. Furthermore, we investigated the concentration of S1P in bilateral petrosal sinus blood samples and observed that the concentration was significantly higher on the adenoma side than that on the nonadenoma side (397.7 ± 15.4 vs. 261.9 ± 14.88; P < 0.05, Figure 2C). Thus, these findings suggested a close association between S1P concentration and the development of ACTH-secreting tumor.

Figure 2
www.frontiersin.orgFigure 2 (A) Representative images of immunofluorescence double staining for SPHK1 (green) and ACTH (pink) in normal pituitary glands and ACTH-secreting pituitary adenomas from the remission and nonremission groups (Normal: n = 3, ACTH pituitary adenoma: remission vs. nonremission: n = 16 vs. 9); scale bars: 100-μm upper and 50-μm lower. (B) Quantitative analysis; white arrows indicate double-positive cells for ACTH and SPHK1. (C) The concentration of S1P in the plasma obtained from the inferior petrosal sinus of the adenoma side and nonadenoma side. ***P < 0.001. Bar represents mean ± SD.

3.3 Combination of interpetrosal S1P and ACTH ratios improved the diagnostic performance for adenoma laterality

The pathology of patients with CD was classified based on adenomatous tissue with ACTH-positive immunostaining into adenoma or nonadenoma sides. To evaluate the correlation between the interpetrosal S1P ratio lateralization and tumor location, we compared the accuracy of predicting tumor laterality using the interpetrosal S1P ratio (>1) and interpetrosal ACTH ratio (>1.4) (the interpetrosal ACTH ratio >1.4 is acknowledged for its positive role in predicting tumor laterality), as well as their combination. Our results indicated that using the interpetrosal S1P or ACTH ratios alone yielded accuracies of 64% and 56% respectively. Notably, the combination of both demonstrated a significantly improved accuracy of 73% (Figure 3A).

Figure 3
www.frontiersin.orgFigure 3 (A) Bar graph illustrating the accuracy of predicting tumor laterality. (B) Receiver operating characteristic (ROC) curve analysis of interpetrosal ACTH ratio to predict tumor location. (C) ROC curve analysis of the interpetrosal S1P ratio to predict tumor location. (D) ROC curve analysis of the combination of the interpetrosal S1P and ACTH ratios to predict tumor location.

Thereafter, the receiver operating characteristic analysis was performed to determine the role of predicting tumor laterality. In particular, the interpetrosal ACTH ratio with an AUC of 75.32% (95% CI: 60.06–97.46%, P < 0.05) and the interpetrosal S1P ratio demonstrated a clinically significant diagnostic accuracy for lateralization, with an AUC of 79.17% (95% CI: 44.40–85.84%, P < 0.05). Furthermore, combining the interpetrosal S1P and ACTH ratios generated an receiver operating characteristic curve with an AUC of 84.09% (95% CI: 52.3–96.77%, P < 0.05) for predicting lateralization with tumor location (cutoff value: interpetrosal S1P ratio ≥1.06, interpetrosal ACTH ratio ≥2.8, 81.82% sensitivity, and 75% specificity) (Figures 3B–D).

3.4 Interpetrosal S1P ratio serves as a predictive factor for early remission in CD

To investigate whether the interpetrosal S1P ratio is associated with early postoperative remission in CD, we compared the baseline interpetrosal S1P ratio between patients with CD in the remission and nonremission groups. Interestingly, we observed that the nonremission group exhibited higher interpetrosal S1P ratios than those of the remission group (median, 1.28 ± 0.25 vs. 1.10 ± 0.09, P = 0.012) (Figure 4).

Figure 4
www.frontiersin.orgFigure 4 Left picture: Scatter plot of bilateral S1P concentrations in the remission and nonremission groups; the slope represents the interpetrosal S1P ratio, blue dots represent the remission group, and red dots represent the nonremission group. Right picture: The interpetrosal S1P ratio in the remission and nonremission groups. *P < 0.05. Bar represents mean ± SD.

To investigate potential factors affecting the interpetrosal S1P ratio, we compared the correlation between interpetrosal S1P ratio and various clinical indicators. This analysis revealed that the interpetrosal S1P ratio positively correlated with preoperative FSH and LH levels, as well as with postoperative 8 am ACTH levels. No significant difference was observed between the interpetrosal S1P ratio and other indicators (Supplementary Figure 4).

4 Discussion

The use of BIPSS involves collection of samples from each inferior petrosal sinus simultaneously, enabling a direct comparison of ACTH concentrations between the left and right petrosal sinuses. BIPSS is used for two purposes: 1) to assist in the differential diagnosis of Cushing’s syndrome; and 2) to determine which side of the pituitary gland contains an adenoma in patients with CD. The interpetrosal ACTH ratio is also useful in determining the location/lateralization of pituitary microadenomas (24, 30, 37), thereby providing guidance to the neurosurgeon during surgery.

To our knowledge, this is the first study to demonstrate that serum S1P levels in patients with CD are significantly higher on the adenoma side of the inferior petrosal sinus than on the nonadenoma side. The interpetrosal S1P ratio exhibited a positive significance in predicting tumor laterality, and the predictive performance was improved when S1P was combined with the interpetrosal ACTH ratio. Notably, the interpetrosal S1P ratio exhibited a positive significance in predicting remission after surgery. Furthermore, the interpetrosal S1P ratio demonstrated a positive and significant correlation with preoperative FSH and LH levels, as well as 8 am ACTH levels on POD1.

ACTH is recognized for its role in controlling the expression of genes involved in steroid production and cortisol synthesis in the human adrenal cortex through sphingolipid metabolism (19). Specifically, ACTH rapidly stimulates SPHK1 activity, leading to an increased in S1P levels, which in turn, increases the expression of multiple steroidogenic proteins (20). Our study demonstrated that higher S1P concentrations were present on the tumor side than on the nontumor side in patients with CD, indicating that the regulatory relationship between ACTH and S1P also exists in ACTH-secreting pituitary adenomas. Several pieces of evidence have supported the potential relationship between S1P and the occurrence of CD. Interestingly, SPHK1 and S1P are known to be integral to the regulation of epidermal growth factor receptor (EGFR) (38), which is highly expressed in human corticotropinomas, where it triggers proopiomelanocortin (the precursor of ACTH) transcription and ACTH synthesis (39). Blocking EGFR activity with an EGFR inhibitor can attenuate corticotroph tumor cell proliferation (40). Furthermore, SPHK1 and proopiomelanocortin share a common transcriptional coactivator, P300 (41, 42). Notably, S1P also directly binds to and inhibits histone deacetylase 2, thereby regulating histone acetylation and gene expression (43). Notably, histone deacetylase 2 expression is deficient in ACTH-pituitary adenomas in CD, contributing to glucocorticoid insensitivity (44), which is a hallmark of CD and a feature associated with nonremission. These studies further demonstrated an association between high S1P ratio and nonremission of CD. Our study, for the first time, established an association between SPHK1/S1P and ACTH adenoma. Nevertheless, further experimental verification is required to confirm the existence of common pathways linking SPHK1 and ACTH. Thus, these findings indicated that the S1P ratio can, to some extent, reflect the differences in ACTH levels and may serve as a surrogate marker for detecting ACTH-secreting pituitary adenomas.

BIPSS is a highly effective procedure for diagnosing pituitary sources of ACTH in CD and remains the gold standard diagnostic method. However, some findings indicated certain limitations associated with the use of the inferior petrosal sinus sampling (IPSS) method in predicting tumor lateralization. The possible causes of error include asymmetrical or underdeveloped petrosal sinus anatomy and placement of the catheter (27). The present study revealed a notable increase in the interpetrosal ACTH ratio among patients with accurate predictions of tumor laterality than among those with inaccurate predictions, although the positive predictive value remained low. These findings suggested that other mechanisms may exist that contribute to false-positive results. The limitations on lateralization highlighted the need for further research to understand the underlying mechanisms contributing to the accuracy of IPSS in predicting tumor lateralization. Further investigation is required to understand these potential mechanisms and improve the accuracy of IPSS in predicting tumor lateralization.

We observed that the interpetrosal S1P ratio was slightly more effective than the ACTH ratio in predicting tumor laterality. However, combining both methods significantly improved the diagnostic sensitivity and specificity. These results have important implications for clinical practice as accurate tumor lateralization is essential for the correct management and treatment of pituitary adenomas. Overall, these findings highlighted the importance of using multiple measures in predicting tumor lateralization and suggested that combining measures may be more effective than relying on any single measure alone. Future research should investigate additional measures to improve the accuracy of tumor lateralization and optimize the use of existing measures for making clinical decisions.

The initial treatment recommendation for CD is surgery. However, long-term surveillance is necessary because of the high recurrence rate (12). Therefore, identifying patients who are at a greater recurrence risk would be helpful in establishing an effective surveillance strategy. Our study revealed that the expression of SPHK1 in pituitary tissue was higher in postoperative nonremission group than in postoperative remission group. Moreover, patients in the nonremission group exhibited significantly higher interpetrosal S1P ratios than those of patients in the remission group. SPHK1 catalyzes the direct phosphorylation synthesis of S1P, and the S1P ratio can thus reflect the expression level of SPHK1 in ACTH tumors. Since S1P can increase the expression of multiple steroidogenic proteins, including steroidogenic acute regulatory protein, 18-kDa translocator protein, low-density lipoprotein receptor, and scavenger receptor class B type I (20), the interpetrosal S1P ratios may be indicative of disease prognosis. This finding is consistent with previous findings indicating the overexpression of SPHK1 is associated with poor prognosis in various neuroendocrine tumors, as factors associated with tumor proliferation, S1P and SPHK1, may play a key role in the proliferation and survival of ACTH pituitary adenomas. The high proportions of SPHK1/ACTH double-positive cells are likely associated with greater phenotypic severity, and CD tumors with this phenotype may have a poor prognosis. These findings hold clinically significance for predicting early postoperative remission in patients with CD. As aforementioned, the interpetrosal S1P ratios have been suggested as a useful diagnostic tool for determining adenoma lateralization in CD, which can also serve as a prognostic indicator for postoperative remission.

Pearson correlation analysis indicated that ACTH 8 am on POD1 and FSH/LH levels were significantly associated with the interpetrosal S1P ratio, suggesting that these pituitary dysfunctions may have a role in the early remission of CD. However, the sample size in this study was relatively small, and further studies with larger sample sizes are needed to confirm these findings. Additionally, other factors affecting surgical outcomes, such as the experience of the surgeon, extent of surgical resection, and use of adjuvant therapy, should be considered when predicting postoperative remission in patients with CD.

This study has some limitations. First, the study was retrospective in design, which limited the control of confounding factors. Additionally, because of the limited sample size, we did not specifically investigate cases where the ACTH ratio failed to accurately identify the correct tumor location. Finally, we did not explore the functional evidence of a common pathway between SPHK1 and ACTH. Despite these limitations, the study contributes to our understanding of the potential utility of the interpetrosal S1P ratio as a biomarker for CD and provides a basis for future research in this area.

In conclusion, our study demonstrated a significant association between the interpetrosal S1P ratio and tumor laterality, as well as in early remission in CD. These findings suggested that the interpetrosal S1P ratio could serve as a useful biomarker in clinical practice. Moreover, targeting genes and drugs related to SPHK1/S1P could provide novel therapeutic strategies for treating CD.

Data availability statement

The original contributions presented in the study are included in the article/Supplementary Material. Further inquiries can be directed to the corresponding author.

Ethics statement

The studies involving humans were approved by The Xiangya Hospital Ethics Committee, Xiangya Hospital (Changsha, China). The studies were conducted in accordance with the local legislation and institutional requirements. The participants provided their written informed consent to participate in this study.

Author contributions

HS: conceptualization, methodology, software, visualization, and investigation. CW and BH: software. YX: writing – review & editing. All authors contributed to the article and approved the submitted version.

Funding

The author(s) declare that no financial support was received for the research, authorship, and/or publication of this article.

Acknowledgments

The authors gratefully acknowledge contributions from the GEO databases and TNMplot database (https://www.tnmplot.com/).

Conflict of interest

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Publisher’s note

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.

Supplementary material

The Supplementary Material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/fendo.2023.1238573/full#supplementary-material

References

1. Tritos NA, Miller K. Diagnosis and management of pituitary adenomas: A review. JAMA (2023) 329(16):1386–98. doi: 10.1001/jama.2023.5444

PubMed Abstract | CrossRef Full Text | Google Scholar

2. Ntali G, Hakami O, Wattegama M, Ahmed S, Karavitaki N. Mortality of patients with cushing’s disease. Exp Clin Endocrinol Diabetes (2021) 129(3):203–7. doi: 10.1055/a-1197-6380

CrossRef Full Text | Google Scholar

3. Hakami O, Ahmed S, Karavitaki N. Epidemiology and mortality of Cushing’s syndrome. Best Pract Res Clin Endocrinol Metab (2021) 35(1):101521. doi: 10.1016/j.beem.2021.101521

PubMed Abstract | CrossRef Full Text | Google Scholar

4. Clayton RN, Raskauskiene D, Reulen RC, Jones PW. Mortality and morbidity in Cushing’s disease over 50 years in Stoke-on-Trent, UK: audit and meta-analysis of literature. J Clin Endocrinol Metab (2011) 96(3):632–42. doi: 10.1210/jc.2010-1942

PubMed Abstract | CrossRef Full Text | Google Scholar

5. Jones PS, Swearingen B. Pituitary surgery in Cushing’s disease: first line treatment and role of reoperation. Pituitary (2022) 25:713–717. doi: 10.1007/s11102-022-01254-8

PubMed Abstract | CrossRef Full Text | Google Scholar

6. Juszczak A, Ertorer ME, Grossman AB. The therapy of cushing’s disease in adults and children: an update. Hormone Metab Res (2012) 45:109–117. doi: 10.1055/s-0032-1330009

CrossRef Full Text | Google Scholar

7. Biller BM, Grossman AB, Stewart PM, Melmed S, Bertagna XY, Bertherat J, et al. Treatment of adrenocorticotropin-dependent Cushing’s syndrome: a consensus statement. J Clin Endocrinol Metab (2008) 93(7):2454–62. doi: 10.1210/jc.2007-2734

PubMed Abstract | CrossRef Full Text | Google Scholar

8. Chandler WF, Barkan AL, Hollon TC, Sakharova AA, Sack JT, Brahma B, et al. Outcome of transsphenoidal surgery for cushing disease: A single-center experience over 32 years. Neurosurgery (2016) 78(2):216–23. doi: 10.1227/NEU.0000000000001011

PubMed Abstract | CrossRef Full Text | Google Scholar

9. Feng M, Liu Z, Liu X, Bao X, Yao Y, Deng K, et al. Diagnosis and outcomes of 341 patients with cushing’s disease following transsphenoid surgery: A single-center experience. World Neurosurg (2018) 109:e75–80. doi: 10.1016/j.wneu.2017.09.105

PubMed Abstract | CrossRef Full Text | Google Scholar

10. Aranda GB, Ensenãat J, Mora M, Puig-Domingo M, Martínez de Osaba MJ, Casals G, et al. Long-term remission and recurrence rate in a cohort of Cushing’s disease: the need for long-term follow-up. Pituitary (2014) 18:142–9. doi: 10.1007/s11102-014-0567-8

CrossRef Full Text | Google Scholar

11. Nieman LK, Biller BM, Findling JW, Murad MH, Newell-Price JD, Savage MO, et al. Treatment of cushing’s syndrome: an endocrine society clinical practice guideline. J Clin Endocrinol Metab (2015) 100(8):2807–31. doi: 10.1210/jc.2015-1818

PubMed Abstract | CrossRef Full Text | Google Scholar

12. Galiana PA, Montañana CF, Suárez PA, Vela JG, Escrivá CM, Lillo VR. Predictors of long-term remission after transsphenoidal surgery in Cushing’s disease. Endocrinol y Nutricioín Oírgano La Sociedad Espanãola Endocrinol y Nutricioín (2013) 60:475–82.

Google Scholar

13. Ayala AR, Manzano AJ. Detection of recurrent Cushing’s disease: proposal for standardized patient monitoring following transsphenoidal surgery. J Neuro-Oncol (2014) 119:235–242. doi: 10.1007/s11060-014-1508-0

CrossRef Full Text | Google Scholar

14. Liu M, Frej C, Langefeld CD, Divers J, Bowden DW, Carr JJ, et al. Plasma apoM and S1P levels are inversely associated with mortality in African Americans with type 2 diabetes mellitus. J Lipid Res (2019) 60:1425–1431. doi: 10.1194/jlr.P089409

PubMed Abstract | CrossRef Full Text | Google Scholar

15. Anderson AK, Lambert JM, Montefusco DJ, Tran BN, Roddy P, Holland WL, et al. Depletion of adipocyte sphingosine kinase 1 leads to cell hypertrophy, impaired lipolysis, and nonalcoholic fatty liver disease. J Lipid Res (2020) 61:1328–1340. doi: 10.1194/jlr.RA120000875

PubMed Abstract | CrossRef Full Text | Google Scholar

16. Smith C, Williams J, Hall C, Casas J, Caley M, O’Toole E, et al. Ichthyosis linked to sphingosine 1-phosphate lyase insufficiency is due to aberrant sphingolipid and calcium regulation. J Lipid Res (2023) 64(4):100351. doi: 10.1016/j.jlr.2023.100351

PubMed Abstract | CrossRef Full Text | Google Scholar

17. Maczis MA, Maceyka M, Waters MR, Newton J, Singh M, Rigsby MF, et al. Sphingosine kinase 1 activation by estrogen receptor α36 contributes to tamoxifen resistance in breast cancer. J Lipid Res (2018) 59:2297–2307. doi: 10.1194/jlr.M085191

PubMed Abstract | CrossRef Full Text | Google Scholar

18. Hii L-W, Chung FF, Mai CW, Yee ZY, Chan HH, Raja VJ, et al. Sphingosine kinase 1 regulates the survival of breast cancer stem cells and non-stem breast cancer cells by suppression of STAT1. Cells (2020) 9(4):886. doi: 10.3390/cells9040886

PubMed Abstract | CrossRef Full Text | Google Scholar

19. Ozbay T, Merrill AH, Sewer MB. ACTH regulates steroidogenic gene expression and cortisol biosynthesis in the human adrenal cortex via sphingolipid metabolism. Endocrine Res (2004) 30:787–794. doi: 10.1081/ERC-200044040

CrossRef Full Text | Google Scholar

20. Lucki NC, Li D, Sewer MB. Sphingosine-1-phosphate rapidly increases cortisol biosynthesis and the expression of genes involved in cholesterol uptake and transport in H295R adrenocortical cells. Mol Cell Endocrinol (2012) 348:165–75. doi: 10.1016/j.mce.2011.08.003

PubMed Abstract | CrossRef Full Text | Google Scholar

21. Lin K, Cheng W, Shen Q, Wang H, Wang R, Guo S, et al. Lipid profiling reveals lipidomic signatures of weight loss interventions. Nutrients (2023) 15(7):1784. doi: 10.3390/nu15071784

PubMed Abstract | CrossRef Full Text | Google Scholar

22. Detomas M, Ritzel K, Nasi-Kordhishti I, Schernthaner-Reiter MH, Losa M, Tröger V, et al. Bilateral inferior petrosal sinus sampling with human CRH stimulation in ACTH-dependent Cushing’s syndrome: results from a retrospective multicenter study. Eur J Endocrinol (2023) 2023:lvad050. doi: 10.1093/ejendo/lvad050

CrossRef Full Text | Google Scholar

23. Zampetti B, Grossrubatscher EM, Dalino Ciaramella P, Boccardi E, Loli P. Bilateral inferior petrosal sinus sampling. Endocrine Connections (2016) 5:R12–R25. doi: 10.1530/EC-16-0029

PubMed Abstract | CrossRef Full Text | Google Scholar

24. Oldfield EH, Doppman JL, Nieman LK, Chrousos GP, Miller DL, Katz D, et al. Petrosal sinus sampling with and without corticotropin-releasing hormone for the differential diagnosis of Cushing’s syndrome. New Engl J Med (1991) 325(13):897–905. doi: 10.1056/NEJM199109263251301

PubMed Abstract | CrossRef Full Text | Google Scholar

25. Oldfield EH, Chrousos GP, Schulte HM, Schaaf M, Mckeever PE, Krudy AG, et al. Preoperative lateralization of ACTH-secreting pituitary microadenomas by bilateral and simultaneous inferior petrosal venous sinus sampling. New Engl J Med (1985) 312(2):100–3. doi: 10.1056/NEJM198501103120207

PubMed Abstract | CrossRef Full Text | Google Scholar

26. Colao A, Faggiano A, Pivonello R, Pecori Giraldi F, Cavagnini F, Lombardi G. Inferior petrosal sinus sampling in the differential diagnosis of Cushing’s syndrome: results of an Italian multicenter study. Eur J Endocrinol (2001) 144(5):499–507. doi: 10.1530/eje.0.1440499

PubMed Abstract | CrossRef Full Text | Google Scholar

27. Lefournier V, Martinie M, Vasdev A, Bessou P, Passagia JG, Labat-Moleur F, et al. Accuracy of bilateral inferior petrosal or cavernous sinuses sampling in predicting the lateralization of Cushing’s disease pituitary microadenoma: influence of catheter position and anatomy of venous drainage. J Clin Endocrinol Metab (2003) 88(1):196–203. doi: 10.1210/jc.2002-020374

PubMed Abstract | CrossRef Full Text | Google Scholar

28. Liu C, Lo JC, Dowd CF, Wilson CB, Kunwar SM, Aron DC, et al. Cavernous and inferior petrosal sinus sampling in the evaluation of ACTH-dependent Cushing’s syndrome. Clin Endocrinol (2004) 61(4):478–86. doi: 10.1111/j.1365-2265.2004.02115.x

CrossRef Full Text | Google Scholar

29. Batista DL, Gennari M, Riar J, Chang R, Keil MF, Oldfield EH, et al. An assessment of petrosal sinus sampling for localization of pituitary microadenomas in children with Cushing disease. J Clin Endocrinol Metab (2006) 91(1):221–4. doi: 10.1210/jc.2005-1096

PubMed Abstract | CrossRef Full Text | Google Scholar

30. Fleseriu M, Auchus R, Bancos I, Ben-Shlomo A, Bertherat J, Biermasz NR, et al. Consensus on diagnosis and management of Cushing’s disease: a guideline update. Lancet Diabetes Endocrinol (2021) 9(12):847–75. doi: 10.1016/S2213-8587(21)00235-7

PubMed Abstract | CrossRef Full Text | Google Scholar

31. Hinojosa-Amaya JoséM, Cuevas-Ramos D. “The definition of remission and recurrence of Cushing’s disease.” Best practice & research. Clin Endocrinol Metab (2021) 35(1):101485. doi: 10.1016/j.beem.2021.101485

CrossRef Full Text | Google Scholar

32. Deipolyi AR, Karaosmanoğlu AD, Habito CM, Brannan SM, Wicky ST, Hirsch JA, et al. The role of bilateral inferior petrosal sinus sampling in the diagnostic evaluation of Cushing syndrome. Diagn Interventional Radiol (2012) 18(1):132–8. doi: 10.4261/1305-3825.DIR.4279-11.0

CrossRef Full Text | Google Scholar

33. Deipolyi AR, Bailin A, Hirsch JA, Walker TG, Oklu R. Bilateral inferior petrosal sinus sampling: experience in 327 patients. J neurointerv Surg (2016) 9:196–199. doi: 10.1136/neurintsurg-2015-012164

PubMed Abstract | CrossRef Full Text | Google Scholar

34. Chongsathidkiet P, Jackson C, Koyama S, Loebel F, Cui X, Farber SH, et al. Sequestration of T-cells in bone marrow in the setting of glioblastoma and other intracranial tumors. Nat Med (2018) 24:1459–1468. doi: 10.1038/s41591-018-0135-2

PubMed Abstract | CrossRef Full Text | Google Scholar

35. Catalino MP, Moore DT, Ironside N, Munoz AR, Coley J, Jonas R, et al. Post-operative serum cortisol and cushing disease recurrence in patients with corticotroph adenomas. J Clin Endocrinol Metab (2023) 2023:dgad347. doi: 10.1210/clinem/dgad347

CrossRef Full Text | Google Scholar

36. Wang F, Catalino MP, Bi WL, Dunn IF, Smith TR, Guo Y, et al. Post-operative day one morning cortisol value as a biomarker to predict long-term remission of cushing disease. J Clin Endocrinol Metab (2021) 106(1):e94-e102. doi: 10.1210/clinem/dgaa773

PubMed Abstract | CrossRef Full Text | Google Scholar

37. Newell-Price JD, Bertagna XY, Grossman AB, Nieman LK. Cushing’s syndrome. Lancet (2005) 367(9522):1605–17. doi: 10.1383/medc.2005.33.11.11

CrossRef Full Text | Google Scholar

38. Tamashiro PM, Furuya H, Shimizu Y, Kawamori T. Sphingosine kinase 1 mediates head & neck squamous cell carcinoma invasion through sphingosine 1-phosphate receptor 1. Cancer Cell Int (2014) 14(1):76. doi: 10.1186/s12935-014-0076-x

PubMed Abstract | CrossRef Full Text | Google Scholar

39. Perez-Rivas LG, Theodoropoulou M, Ferraù F, Nusser C, Kawaguchi K, Stratakis CA, et al. The gene of the ubiquitin-specific protease 8 is frequently mutated in adenomas causing cushing’s disease. J Clin Endocrinol Metab (2015) 100(7):E997–1004. doi: 10.1210/jc.2015-1453

PubMed Abstract | CrossRef Full Text | Google Scholar

40. Fukuoka H, Cooper O, Ben-Shlomo A, Mamelak A, Ren SG, Bruyette D, et al. EGFR as a therapeutic target for human, canine, and mouse ACTH-secreting pituitary adenomas. J Clin Invest (2011) 121(12):4712–21. doi: 10.1172/JCI60417

PubMed Abstract | CrossRef Full Text | Google Scholar

41. Postepska-Igielska A, Giwojna A, Gasri-Plotnitsky L, Schmitt N, Dold A, Ginsberg D, et al. LncRNA khps1 regulates expression of the proto-oncogene SPHK1 via triplex-mediated changes in chromatin structure. Mol Cell (2015) 60(4):626–36. doi: 10.1016/j.molcel.2015.10.001

PubMed Abstract | CrossRef Full Text | Google Scholar

42. Smith RG, Betancourt L, Sun Y. Molecular endocrinology and physiology of the aging central nervous system. Endocrine Rev (2005) 26(2):203–50. doi: 10.1210/er.2002-0017

CrossRef Full Text | Google Scholar

43. Hait NC, Allegood J, Maceyka M, Strub GM, Harikumar KB, Singh SK, et al. Regulation of histone acetylation in the nucleus by sphingosine-1-phosphate. Science (2009) 325:1254–7. doi: 10.1126/science.1176709

PubMed Abstract | CrossRef Full Text | Google Scholar

44. Bilodeau S, Vallette-Kasic S, Gauthier Y, Figarella-Branger D, Brue T, Berthelet F, et al. Role of Brg1 and HDAC2 in GR trans-repression of the pituitary POMC gene and misexpression in Cushing disease. Genes Dev (2006) 20:2871–86. doi: 10.1101/gad.1444606

PubMed Abstract | CrossRef Full Text | Google Scholar

Keywords: ipss, sphingosine-1-phosphate, Cushing’s disease, remission, tumor laterality

Citation: Sun H, Wu C, Hu B and Xiao Y (2023) Interpetrosal sphingosine-1-phosphate ratio predicting Cushing’s disease tumor laterality and remission after surgery. Front. Endocrinol. 14:1238573. doi: 10.3389/fendo.2023.1238573

Received: 12 June 2023; Accepted: 17 October 2023;
Published: 31 October 2023.

Edited by:

Anton Luger, Medical University of Vienna, Austria

Reviewed by:

Guangwei Wang, Hunan University of Medicine, China
Marie Helene Schernthaner-Reiter, Medical University of Vienna, Austria

Copyright © 2023 Sun, Wu, Hu and Xiao. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

*Correspondence: Yuan Xiao, xiaoyuan2021@csu.edu.cn

Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.

From https://www.frontiersin.org/articles/10.3389/fendo.2023.1238573/full

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Bilateral Inferior Petrosal Sinus Sampling: Validity, Diagnostic Accuracy in Lateralization of Pituitary Microadenoma, and Treatment In Eleven Patients with Cushing’s Syndrome – a Single-Center Retrospective Cohort Study

Posted on November 17, 2023 by MaryO

Abstract

Background

This single-center retrospective cohort study aimed to describe the findings and validity of Bilateral inferior petrosal sinus sampling (BIPSS) in the differential diagnosis of patients with ACTH-dependent Cushing’s syndrome (CS).

Methods

Eleven patients underwent BIPSS due to equivocal biochemical tests and imaging results. Blood samples were taken from the right inferior petrosal sinus (IPS), left IPS, and a peripheral vein before and after stimulation with desmopressin (DDAVP). ACTH and prolactin levels were measured. The diagnosis was based on the ACTH ratio between the IPS and the peripheral vein. Also, lateralization of pituitary adenoma in patients with Cushing’s disease (CD) was predicted. No significant complications were observed with BIPSS.

Results

Based on the pathology report, eight patients had CD, and three had ectopic ACTH syndrome (EAS). Unstimulated BIPSS resulted in a sensitivity of 87.5%, specificity of 100%, PPV of 100%, NPV of 75%, and accuracy of 91%. Stimulated BIPSS resulted in a sensitivity of 100%, specificity of 100%, PPV of 100%, NPV of 100%, and accuracy of 100%. However, pituitary magnetic resonance imaging (MRI) had a lower diagnostic accuracy (sensitivity:62.5%, specificity:33%, PPV:71%, NPV:25%, accuracy:54%). BIPSS accurately demonstrated pituitary adenoma lateralization in 75% of patients with CD.

Conclusions

This study suggests that BIPSS may be a reliable and low-complication technique in evaluating patients with ACTH-dependent CS who had inconclusive imaging and biochemical test results. The diagnostic accuracy is improved by DDAVP stimulation. Pituitary adenoma lateralization can be predicted with the aid of BIPSS.

Peer Review reports

Introduction

All disorders with manifestations associated with glucocorticoid excess are called Cushing’s syndrome. Exogenous corticosteroids cause most CS cases, and endogenous CS cases are rare [1, 2].

The diagnosis of Cushing’s syndrome may be complicated, particularly in cases with ambiguous clinical findings, atypical presentations, and cyclic hypercortisolemia [3,4,5]. The initial laboratory tests for diagnosis of CS include 24-hour urinary free cortisol (UFC), late-night salivary cortisol, and low-dose dexamethasone suppression test (DST). These tests only represent hypercortisolemia [1, 2].

Once CS is diagnosed, further evaluations are needed to identify the etiology. The first step is to measure the plasma ACTH level. A low plasma ACTH level indicates ACTH-independent CS and a high level suggests ACTH-dependent CS. Normal ACTH can also occur in ACTH-dependent CS. Almost all cases of ACTH-dependent are due to pituitary adenoma (Cushing’s disease) or EAS [1, 2, 6].

Some ectopic sources include neuroendocrine tumors, bronchial carcinoma, and pancreatic carcinoma [7, 8]. Because of the high mortality in tumors associated with EAS, it is essential to differentiate CD from EAS.

To distinguish CD from EAS, a high-dose dexamethasone suppression test (HDDST), corticotropin-releasing hormone (CRH), or DDAVP stimulation tests, or pituitary MRI is recommended [1, 2, 6, 9,10,11,12]. MRI can be equivocal in half of the patients, and only relatively large lesions (> 6 mm) detected on MRI reliably confirm the diagnosis of CD with biochemical confirmation and expected clinical symptoms [9].

Considering the relatively low sensitivity and specificity of non-invasive tests [13, 14] and the high complications of the surgery, it seems reasonable to use a test with high sensitivity and specificity and few complications before resection. BIPSS with CRH or DDAVP stimulation can be helpful for further evaluation [1, 2, 10, 15, 16]. The BIPSS procedure is the same in both stimulation methods. Due to its lower cost, availability, and comparable diagnostic accuracy, using DDAVP instead of CRH for BIPSS is an alternative [17, 18]. BIPSS has been reported to have high sensitivity and specificity and is a safe procedure when performed by experienced interventional radiologists [15, 16, 19, 20].

This case series describes the experience with BIPSS and examines the validity of BIPSS for differentiating CD from EAS in patients with ACTH-dependent CS who had ambiguous or equivocal results in non-invasive tests.

Materials and methods

Patients

This retrospective cohort study included 11 patients with ACTH-dependent CS who underwent BIPSS between 2018 and 2020 in a tertiary care hospital.

Data collection

Well-trained nurses conducted anthropometric measurements, including height and weight. Standing height was measured with a portable stadiometer (rounded to the nearest 0.1 cm). Using a calibrated balance beam scale, this study measured weight in the upright position (rounded to the nearest 0.1 kg). Body mass index (BMI) was calculated by dividing weight (kg) by height squared (m2). Well-trained examiners measured blood pressure (systolic and diastolic) at the left arm in the sitting position after 5 min of rest using a calibrated mercury sphygmomanometer. The blood sample was taken, and fasting blood sugar (FBS), hemoglobin (Hb), potassium (K), and creatinine (Cr) were measured. All research was performed in accordance with the Declaration of Helsinki. Informed consent was obtained from all participants or their legal guardians.

Biochemical tests and imaging

Patients with signs and symptoms of CS underwent screening evaluations, and confirmatory tests were performed using serum cortisol and 24-hour UFC. After confirmation of CS, ACTH was measured using an immunoradiometric assay to categorize patients into ACTH-dependent or independent groups. ACTH test was performed with SIEMENS IMMULITE 2000 device with an analytical sensitivity of 5 pg/ml (1.1 pmol/l) and CV ∼7.5%. HDDST was conducted by administering 2 mg dexamethasone every 6 h for 48 h to all patients, and then serum cortisol and 24-hour UFC were rechecked. A pituitary MRI was performed with sagittal and coronal T1- and T2-weighted images before and after the gadolinium injection.

BIPSS procedure

After biochemical tests and imaging, an experienced interventional radiologist performed bilateral and simultaneous catheterization of the inferior petrosal sinuses. Venography was obtained to evaluate venous anatomy and catheter placement. The retrograde flow of contrast dye into the contralateral cavernous sinuses was used as a marker of adequate sampling. After the correct placement of catheters, blood samples were obtained from each of three ports (peripheral (P), left inferior petrosal sinus (IPS), and right IPS) at -15, -10, -5, and 0 min. The current study used DDAVP for stimulation. After peripheral injection of 10 micrograms of DDAVP, blood samples from these three sites were obtained at + 3, +5, + 10, and + 15 min. Three samples from these sites were also obtained to measure prolactin. Upon collection, BIPSS samples were placed in an ice-water bath. At the end of the procedure, samples were taken to the laboratory, where the plasma was separated and used for immediate measurement of ACTH. Specimens were refrigerated, centrifuged, frozen, and assayed within 24 h.

After the samples were obtained, both femoral sheaths were removed, and manual compression was used to obtain hemostasis before transferring patients to the recovery room. The whole procedure took 1–2 h. Patients underwent strict bed rest for 4 h before discharge on the same day. All BIPSS were performed without significant complications, and only hematoma at the catheterization site was observed in some patients.

BIPSS interpretation

The ratio of IPS ACTH to peripheral ACTH level (IPS/P ACTH) for each side was calculated. Baseline sampling at minute 0 with IPS/P ≥ 2 or stimulated sampling at minute 3 with 1PS/P ≥ 3 is confirmatory for CD [1, 8]. Also, the IPS/P ratio was checked for prolactin level after DDAVP stimulation (stimulated IPS/P prolactin). A stimulated IPS/P prolactin ≥ 1.8 indicates successful catheterization, meaning the catheter is correctly placed in the IPS [21]. For further evaluation, the current study normalized the ACTH to the prolactin level by dividing stimulated IPS/P ACTH into stimulated IPS/P prolactin for each side. A normalized ACTH/prolactin IPS/P ratio ≥ 1.3 supports a pituitary ACTH source (Cushing’s disease), and a normalized ratio ≤ 0.7 an ectopic source (EAS) [22]. The values between 0.7 and 1.3 are equivocal. The inter-sinus ratio was defined as the ratio of the IPS/P ACTH level of one side with the higher level divided by the IPS/P ACTH level of the other side with the lower level, either before or after stimulation. An inter-sinus ratio ≥ 1.4 indicates lateralization to the side with a higher IPS/P ACTH level [23].

Statistical analysis

This analysis used SPSS software version 18 (SPSS, Inc.) to perform analyses. Data were expressed as numbers and percentages. Continuous variables were presented as means (± SD). This study reported the median or range when the data did not follow a normal distribution. The Shapiro-Wilk test was used to test for normality. The nonparametric Mann-Whitney U Test was utilized to compare variables. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of the tests were calculated based on standard statistical equations.

Results

Baseline characteristics and clinical manifestations

This retrospective research studied 11 patients with ACTH-dependent CS, including eight females (72.7%) and three (27.3%) males. The median (Q1-Q3) age was 32.0 (22–45) years. The median (Q1-Q3) of BMI, systolic blood pressure (SBP), diastolic blood pressure (DBP), FBS, Hb, K, and Cr were 29.2 (24.8–33.3), 130.0 (125–140), 80.0 (80–95), 98.0 (88–103), 13.5 (12.4–13.9), 4.2 (3.9–4.5), and 1.0 (0.9–1.1), respectively. The demographic characteristics of patients are presented in Table 1. The Hb levels were not different in women and men (median 13.35 vs. 13.70, p-value = 0.776). In addition, no statistical difference between patients with a final diagnosis of CD and EAS was detected for Hb levels (Total: median 13.60 vs. 13.2, p-value > 0.05) (Women: median 13.5 vs. 13.2, p-value > 0.05) (Men: median 13.7 vs. 13.25, p-value > 0.05).

Table 1 Demographic characteristics of the studied patients

90% of patients had at least one skin manifestation, such as striae, easy bruising, acne, hyperpigmentation, hirsutism, hair loss, edema, and hypertrichosis. Other symptoms were hypertension (HTN) (81%), reproductive dysfunction (81%), including infertility, oligomenorrhea, loss of libido, weight gain (72%), proximal muscle weakness (45%), and headache (27%) (Table 2).

Table 2 Clinical manifestations of the studied patients

Results of biochemical tests

Biochemical tests results, including basal serum cortisol (median:26 mcg/dl, range:15-54.5 mcg/dl), basal 24-hour UFC (median:670 mcg/dl, range:422–1545 mcg/dl), ACTH (median:58.8 pg/ml, range:25–155 pg/ml), serum cortisol after HDDST (median:14.2 mcg/dl, range:2.63-36.0 mcg/dl), 24-hour UFC after HDDST (median:292 mcg/dl, range:29.5–581 mcg/dl) are presented in Table 3. According to the basal serum cortisol results, eight patients (Cases 1, 3, 5, 7, 8, 9, 10, and 11) had basal serum cortisol levels > 22 mcg/dl, which indicates hypercortisolemia. Other patients (Cases 2, 4, and 6) had basal serum cortisol in the normal range (5–25 mcg/dl) and were considered as false negative results of this test.

Table 3 The results of biochemical tests in the studied patients

All patients had elevated basal 24-hour UFC levels (422–1545 mcg/dl), indicative of hypercortisolemia (Table 3).

There were six patients with elevated peripheral ACTH levels (> 58 pg/ml) (cases 5, 6, 8, 9, 10, and 11). Other patients had ACTH within the normal range (6–58 pg/ml) (cases 1, 2, 3, 4, 7) (Table 3).

None of the patients showed suppression after 1 mg DST. After HDDST, cases 2, 3, 8, and 10 had more than 50% suppression of serum cortisol. In the other six patients, serum cortisol was not suppressed or suppressed by less than 50%. In one patient, serum cortisol levels were not measured (case 1) because the sample was not stored under standard test conditions.

Also, eight patients had more than 50% 24-hour UFC suppression after HDDST (cases 1, 2, 3, 4, 6, 7, 9, and 10). In two patients, 24-hour UFC was suppressed less than 50% (cases 5 and 11), and in one patient (case 8), the 24-hour UFC sample was not tested due to the non-standard condition of the sample.

BIPSS results

BIPSS results before and after stimulation are shown in Table 4. The baseline value (sampling at minute 0) of IPS/P ACTH ≥ 2 confirms CD. According to this ratio, cases 1,3,4,5,6,7, and 8 were diagnosed as CD. The unilateral source for CD was confirmed in cases 1, 3, 7, and 8. BIPPS didn’t demonstrate lateralization in cases 4, 5, and 6.

Table 4 Baseline and stimulated IPS/P ratio for ACTH and Prolactin in the studied patients

The highest IPS/P ACTH ratio was 3 min after the DDAVP injection. A sampling at minute 3 with stimulated IPS/P ACTH ≥ 3 confirms CD. This ratio confirmed CD in cases 1–8 and showed a unilateral source for CD in cases 1, 2, 3, and 7. The ratio didn’t demonstrate lateralization in cases 4, 5, 6, and 8. The stimulated IPS/P prolactin was ≥ 1.8 in all cases.

The variability in the IPS/P ACTH ratio in patients with CD is shown in Fig. 1. The peak of this ratio was 3 min after the DDAVP injection. In patients with EAS, there were no changes before or after the DDAVP stimulation.

Fig. 1

figure 1

Comparison of mean values of IPS/P ACTH in CD (Lt.) and EAS (Rt.). IPS; inferior petrosal sinus; P: peripheral; ACTH: adrenocorticotropic hormone; CD: Cushing’s disease; EAS: ectopic ACTH syndrome; Lt: left; Rt: right

According to the Prolactin-normalized ACTH IPS/P ratios, eight patients (cases 1–8) were diagnosed as CD and three as EAS (cases 9–11). In cases 1, 2, 3, 7, and 8, unilateral sources of CD were confirmed, but in cases 4,5 and 6, bilateral sources were detected (Table 4).

According to the inter-sinus ratio, BIPSS could lateralize the source of ACTH in all patients with CD. The inter-sinus ratio in patients with EAS could not lateralize any pituitary source for ACTH (Table 4).

In five patients with CD and one with EAS, the highest peripheral ACTH level was observed 15 min after stimulation. Two patients with CD and one with EAS had the highest peripheral ACTH level 10 min after stimulation. Only one patient with CD and one with EAS had the highest peripheral ACTH level 5 min after stimulation. No patient had maximum peripheral ACTH levels in the first post-stimulation sample (minute 3).

The larger numerator or smaller denominator produces a higher value in a ratio. In the samples obtained immediately after stimulation, the highest concentration of ACTH was in the IPS, and the lowest was in the peripheral blood. Therefore, as mentioned, the highest post-stimulation value of the IPS/P ACTH ratio was obtained at minute 3.

MRI results

MRI results showed pituitary adenoma in five patients, enhancement in one patient, pituitary mass and lesion in two patients, empty sella in two patients, and possible pituitary adenoma and adrenal mass in one patient (Table 5).

Table 5 Final diagnosis, lateralization, MRI results, and management

Immunohistochemistry (IHC) results

According to the pathology report, eight patients were confirmed as CD (Table 5). The other two patients were EAS (one carcinoid tumor of the lung and one pheochromocytoma). One patient had no documented pathologic source of hypercortisolemia because the patient did not consent to surgery, and the diagnosis of EAS was made based on the results of biochemical tests.

BIPSS vs. MRI results

MRI results showed pituitary adenoma in five patients with CD. MRI and BIPSS showed the adenoma on a similar side in two of them. In the other three patients, MRI showed bilateral adenoma, but BIPSS lateralized the adenoma to one side. One of the other three patients had only left-sided enhancement but no overt adenoma on MRI, whereas BIPSS lateralized the adenoma to the right side. One patient had a low-signal pituitary mass on the right side on MRI, and BIPSS also lateralized to the right. Another patient with a history of transsphenoidal surgery (TSS), diagnosed as recurrent CD, had a partially empty sella. MRI was equivocal, but BIPSS lateralized to the left side.

Among patients with EAS, one with an equivocal BIPSS result had an empty sella on MRI. Two other patients had pituitary lesions on MRI, but BIPSS results were equivocal.

Comparison between BIPSS, MRI, and surgery

Among patients with CD, the final diagnosis based on surgery in three patients was consistent with MRI and BIPSS results and lateralized the adenoma on the same side. In one patient, the surgery result was similar to the MRI findings and showed bilateral adenoma, but BIPSS showed adenoma on the left side. In the patient with equivocal MRI findings and a history of TSS, IHC could not identify ACTH +, although BIPSS lateralized to the left side. In three other patients, surgery results were concordant with BIPSS and lateralized the adenoma on the same side, although MRI showed discordant results.

Validity of BIPSS

Baseline IPS/P ACTH resulted in a sensitivity of 87.5%, specificity of 100%, PPV of 100%, NPV of 75%, and accuracy of 91%. Stimulation with DDAVP improved validity. Both stimulated IPS/P ACTH and normalized ACTH/prolactin IPS/P ratio resulted in a sensitivity of 100%, specificity of 100%, PPV of 100%, NPV of 100%, and accuracy of 100%. BIPSS, either unstimulated or stimulated, had higher validity than MRI, with a sensitivity of 62.5%, specificity of 33%, PPV of 71%, NPV of 25%, and accuracy of 54%. BIPSS accurately predicted pituitary adenoma lateralization in 75% of patients with CD.

Discussion

In this study, BIPSS before stimulation showed a sensitivity of 87.5% and a specificity of 100%. However, BIPSS after stimulation showed a sensitivity of 100% and specificity of 100%. It has been demonstrated that the sensitivity of BIPSS can vary from 88 to 100%, and its specificity from 67 to 100% in the diagnosis of CD [24]. Previous studies have reported sensitivity and specificity of more than 80% and 90% for BIPSS, and the combination of BIPSS with stimulation by CRH or DDAVP improves the sensitivity and specificity to more than 95 and 100%, respectively [15, 19, 25]. Chen et al. suggested the optimal IPS:P cutoff value of 1.4 before and 2.8 after stimulation [20]. Considering these cutoffs, the only patient in this study who was negative for CD before stimulation becomes positive, and the sensitivity before stimulation increases from 87.5 to 100%. The diagnostic accuracy after stimulation remains unchanged. Results of the current study showed that BIPSS is highly valued in final diagnosis, even without stimulation.

In this investigation, the utilization of Prolactin-normalized ACTH IPS/P ratios exhibited a sensitivity and specificity of 100% for the CD diagnosis. This finding aligns with research conducted by Detomas et al., which reported a sensitivity of 96% and specificity of 100% for the normalized ACTH: Prolactin IPS/P ratio [26]. It seems that concurrently assessing prolactin levels may potentially enhance the diagnostic accuracy of BIPSS. However, the current literature is inconsistent. Some studies do not support the use of prolactin to diagnose CD [27].

In all patients, the IPS/P ACTH ratio at minute 15 did not show a considerable difference from this ratio at minute 0. Previous studies have shown that sampling at minute 15 is not helpful for diagnosis [1, 15, 20, 28]. Unlike the IPS/P ACTH ratio, six patients had the highest peripheral ACTH level at minute 15 after stimulation, but no patient had it at minute 3 after stimulation. However, more studies are needed to obtain more precise results, and this study’s sample size was limited.

BIPSS accurately lateralized the adenoma in six patients with CD, but MRI was able to lateralize the adenoma in two patients correctly. BIPSS had higher validity than MRI in differentiating CD from EAS, both with and without stimulation. The current literature is controversial. Colao et al. reported that adenoma could be accurately localized in 65% of patients using IPSS [23]. However, Lefournier et al. showed that the diagnostic accuracy of IPSS in identifying the side of the pituitary adenoma was 57% [28]. Wind et al. showed that the PPV for IPSS to identify the tumor side correctly was 69%. Additionally, MRI was more accurate than IPSS in tumor lateralization [29]. Earlier studies have shown that MRI may show a pituitary lesion, and BIPSS indicates a pituitary adenoma. However, the lesion observed on the MRI is not related to the pituitary adenoma [1, 15, 19, 25, 28]. Also, MRI may show pituitary lesions, while BIPSS indicates EAS.

In the current study, the concordance of IHC results with BIPSS and MRI findings was inconclusive, possibly due to the limited number of patients. However, there is disagreement about the role of pathological study in diagnosis [19, 28].

Eight patients had elevated basal serum cortisol levels in this study (Sensitivity:73%). Instead, all patients had hypercortisolemia according to basal 24-hour UFC results, and no false-negative results were observed (Sensitivity:100%). This study’s findings were consistent with previous studies regarding low sensitivity for basal serum cortisol and high sensitivity for 24-hour UFC as screening tests for hypercortisolemia [6, 30, 31].

After HDDST, basal serum cortisol suppression was observed in three patients with CD (cases 2, 3, and 8) but not in the others with CD. Also, serum cortisol levels were suppressed after HDDST in a patient with EAS who had a lung carcinoid tumor. Arnaldi et al. showed that some carcinoid tumors might be sensitive to HDDST, and suppression of serum cortisol may be observed after this test [1, 32]. After HDDST, six patients with CD had suppressed 24-hour UFC, but one did not show more than 50% suppression. Two patients with EAS had more than 50% 24-hour UFC suppression.

According to the final pathology report, the sensitivity of serum and urine cortisol level tests after HDDST was 43% and 86%, and the specificity was 67% and 33%, respectively. PPV in both was 75%, NPV was 33% and 50%, and accuracy was 50% and 70%, respectively, which shows that these preliminary tests cannot be a good guide for the final diagnosis and subsequent treatment planning. Previous studies showed that more than one biochemical test could improve the accuracy for differentiating between CD and EAS [1, 5, 6, 9, 31]. The current study confirms the importance of using more than one biochemical test for diagnosing hypercortisolemia and diagnosing CD from EAS.

Detomas et al. reported that Hb levels were high in females with CS while they were low in males with CS. Furthermore, there were lower levels of Hb in EAS than in CD in females [33]. In the current study, the Hb levels were not different in women and men. Furthermore, no statistical difference was observed for Hb levels between patients with a final diagnosis of CD and EAS. Hb levels did not contribute to diagnosing ACTH-dependent CS in this analysis.

There were some limitations in this study. First, the sample size was relatively small. Second, it was a retrospective study. Further studies could investigate the BIPSS in a larger sample size and determine the validity of this method in patients with CS.

Conclusions

The current study suggests that BIPSS can be a reliable and low-complication method in evaluating patients with ACTH-dependent CS who had equivocal results in imaging and biochemical tests, even before stimulation. Stimulation with DDAVP increases diagnostic accuracy. BIPSS can be used to predict the lateralization of the pituitary adenoma.

Data Availability

All data generated or analyzed during this study are included in this published article.

Abbreviations

BIPSS:
Bilateral inferior petrosal sinus sampling
ACTH:
Adrenocorticotropic hormone
CS:
Cushing’s syndrome
IPS:
Inferior petrosal sinus
DDAVP:
Desmopressin
CD:
Cushing’s disease
EAS:
Ectopic ACTH syndrome
MRI:
Magnetic resonance imaging
UFC:
Urinary free cortisol
DST:
Dexamethasone suppression test
HDDST:
High-dose dexamethasone suppression test
CRH:
Corticotropin-releasing hormone
BMI:
Body mass index
FBS:
Fasting blood glucose
Hb:
Hemoglobin
Cr:
Creatinine
PPV:
Positive predictive value
NPV:
Negative predictive value
SBP:
Systolic blood pressure
DBP:
Diastolic blood pressure
K:
Potassium
HTN:
Hypertension
IHC:
Immunohistochemistry
TSS:
Transsphenoidal surgery

References

  1. Arnaldi G, Angeli A, Atkinson A, Bertagna X, Cavagnini F, Chrousos G, et al. Diagnosis and Complications of Cushing’s syndrome: a consensus statement. J Clin Endocrinol Metabolism. 2003;88(12):5593–602.

    Article CAS Google Scholar

  2. Sharma ST, Nieman LK, Feelders RA. Cushing’s syndrome: epidemiology and developments in Disease management. Clin Epidemiol. 2015;7:281.

    PubMed PubMed Central Google Scholar

  3. Boscaro M, Barzon L, Sonino N. The diagnosis of Cushing’s syndrome: atypical presentations and laboratory shortcomings. Arch Intern Med. 2000;160(20):3045–53.

    Article CAS PubMed Google Scholar

  4. Atkinson AB, Kennedy AL, Carson DJ, Hadden DR, Weaver JA, Sheridan B. Five cases of cyclical Cushing’s syndrome. Br Med J (Clin Res Ed). 1985;291(6507):1453–7.

    Article CAS PubMed Google Scholar

  5. Velez DA, Mayberg MR, Ludlam WH. Cyclic Cushing syndrome: definitions and treatment implications. NeuroSurg Focus. 2007;23(3):1–3.

    Article Google Scholar

  6. Nieman LK, Biller BM, Findling JW, Newell-Price J, Savage MO, Stewart PM, et al. The diagnosis of Cushing’s syndrome: an endocrine society clinical practice guideline. J Clin Endocrinol Metabolism. 2008;93(5):1526–40.

    Article CAS Google Scholar

  7. Isidori AM, Kaltsas GA, Pozza C, Frajese V, Newell-Price J, Reznek RH, et al. The ectopic adrenocorticotropin syndrome: clinical features, diagnosis, management, and long-term follow-up. J Clin Endocrinol Metabolism. 2006;91(2):371–7.

    Article CAS Google Scholar

  8. Lad SP, Patil CG, Laws ER, Katznelson L. The role of inferior petrosal sinus sampling in the diagnostic localization of Cushing’s Disease. NeuroSurg Focus. 2007;23(3):1–6.

    Article Google Scholar

  9. Gross BA, Mindea SA, Pick AJ, Chandler JP, Batjer HH. Diagnostic approach to Cushing Disease. NeuroSurg Focus. 2007;23(3):1–7.

    Google Scholar

  10. Tomycz ND, Horowitz MB. Inferior petrosal sinus sampling in the diagnosis of sellar neuropathology. Neurosurg Clin North Am. 2009;20(3):361–7.

    Article Google Scholar

  11. Ceccato F, Barbot M, Mondin A, Boscaro M, Fleseriu M, Scaroni C. Dynamic testing for Differential diagnosis of ACTH-Dependent Cushing Syndrome: a systematic review and Meta-analysis. J Clin Endocrinol Metabolism. 2022;108(5):e178–e88.

    Article Google Scholar

  12. Detomas M, Ritzel K, Nasi-Kordhishti I, Wolfsberger S, Quinkler M, Losa M et al. Outcome of CRH stimulation test and overnight 8 mg dexamethasone suppression test in 469 patients with ACTH-dependent Cushing’s syndrome. Front Endocrinol. 2022;13.

  13. Ezzat S, Asa SL, Couldwell WT, Barr CE, Dodge WE, Vance ML, et al. The prevalence of pituitary adenomas: a systematic review. Cancer: Interdisciplinary International Journal of the American Cancer Society. 2004;101(3):613–9.

    Article Google Scholar

  14. Javorsky BR, Findling JW. Inferior petrosal sampling for the differential diagnosis of ACTH-dependent Cushing’s syndrome. Cushing’s Syndrome: Springer; 2010. pp. 105–19.

    Google Scholar

  15. Deipolyi A, Bailin A, Hirsch JA, Walker TG, Oklu R. Bilateral inferior petrosal sinus sampling: experience in 327 patients. J NeuroInterventional Surg. 2017;9(2):196–9.

    Article Google Scholar

  16. Valizadeh M, Ahmadi AR, Ebadinejad A, Rahmani F, Abiri B. Diagnostic accuracy of bilateral inferior petrosal sinus sampling using desmopressin or corticotropic-releasing hormone in ACTH-dependent Cushing’s syndrome: a systematic review and meta-analysis. Reviews in Endocrine and Metabolic Disorders. 2022:1–12.

  17. Pinelli S, Barbot M, Scaroni C, Ceccato F. Second-line tests in the diagnosis of adrenocorticotropic hormone-dependent hypercortisolism. Ann Lab Med. 2021;41(6):521–31.

    Article PubMed PubMed Central Google Scholar

  18. Zampetti B, Grossrubatscher E, Dalino Ciaramella P, Boccardi E, Loli P. Bilateral inferior petrosal sinus sampling. Endocr Connect. 2016;5(4):R12–25.

    Article CAS PubMed PubMed Central Google Scholar

  19. Wang H, Ba Y, Xing Q, Cai R-C. Differential diagnostic value of bilateral inferior petrosal sinus sampling (BIPSS) in ACTH-dependent Cushing syndrome: a systematic review and Meta-analysis. BMC Endocr Disorders. 2020;20(1):1–11.

    Article Google Scholar

  20. Chen S, Chen K, Wang S, Zhu H, Lu L, Zhang X, et al. The optimal cut-off of BIPSS in differential diagnosis of ACTH-dependent Cushing’s syndrome: is stimulation necessary? J Clin Endocrinol Metabolism. 2020;105(4):e1673–e85.

    Article Google Scholar

  21. Qiao X, Ye H, Zhang X, Zhao W, Zhang S, Lu B, et al. The value of prolactin in inferior petrosal sinus sampling with desmopressin stimulation in Cushing’s Disease. Endocrine. 2015;48(2):644–52.

    Article CAS PubMed Google Scholar

  22. Sharma ST, Nieman LK. Is prolactin measurement of value during inferior petrosal sinus sampling in patients with adrenocorticotropic hormone-dependent Cushing’s syndrome? J Endocrinol Investig. 2013;36(11):1112–6.

    CAS Google Scholar

  23. Colao A, Faggiano A, Pivonello R, Giraldi FP, Cavagnini F, Lombardi G. Inferior petrosal sinus sampling in the differential diagnosis of Cushing’s syndrome: results of an Italian multicenter study. Eur J Endocrinol. 2001;144(5):499–507.

    Article CAS PubMed Google Scholar

  24. Perlman JE, Johnston PC, Hui F, Mulligan G, Weil RJ, Recinos PF, et al. Pitfalls in performing and interpreting inferior petrosal sinus sampling: personal experience and literature review. J Clin Endocrinol Metabolism. 2021;106(5):e1953–e67.

    Article Google Scholar

  25. Castinetti F, Morange I, Dufour H, Jaquet P, Conte-Devolx B, Girard N, et al. Desmopressin test during petrosal sinus sampling: a valuable tool to discriminate pituitary or ectopic ACTH-dependent Cushing’s syndrome. Eur J Endocrinol. 2007;157(3):271–7.

    Article CAS PubMed Google Scholar

  26. Detomas M, Ritzel K, Nasi-Kordhishti I, Schernthaner-Reiter MH, Losa M, Tröger V, et al. Bilateral inferior petrosal sinus sampling with human CRH stimulation in ACTH-dependent Cushing’s syndrome: results from a retrospective multicenter study. Eur J Endocrinol. 2023;188(5):448–56.

    Article Google Scholar

  27. De Sousa SMC, McCormack AI, McGrath S, Torpy DJ. Prolactin correction for adequacy of petrosal sinus cannulation may diminish diagnostic accuracy in Cushing’s Disease. Clin Endocrinol (Oxf). 2017;87(5):515–22.

    Article PubMed Google Scholar

  28. Lefournier V, Martinie M, Vasdev A, Bessou P, Passagia J-G, Labat-Moleur Fo, et al. Accuracy of bilateral inferior petrosal or cavernous sinuses sampling in predicting the lateralization of Cushing’s Disease pituitary microadenoma: influence of catheter position and anatomy of venous drainage. J Clin Endocrinol Metabolism. 2003;88(1):196–203.

    Article CAS Google Scholar

  29. Wind JJ, Lonser RR, Nieman LK, DeVroom HL, Chang R, Oldfield EH. The lateralization accuracy of inferior petrosal sinus sampling in 501 patients with Cushing’s Disease. J Clin Endocrinol Metab. 2013;98(6):2285–93.

    Article CAS PubMed PubMed Central Google Scholar

  30. Elamin MB, Murad MH, Mullan R, Erickson D, Harris K, Nadeem S, et al. Accuracy of diagnostic tests for Cushing’s syndrome: a systematic review and metaanalyses. J Clin Endocrinol Metabolism. 2008;93(5):1553–62.

    Article CAS Google Scholar

  31. Pecori Giraldi F, Ambrogio AG, De Martin M, Fatti LM, Scacchi M, Cavagnini F. Specificity of first-line tests for the diagnosis of Cushing’s syndrome: assessment in a large series. J Clin Endocrinol Metabolism. 2007;92(11):4123–9.

    Article Google Scholar

  32. Terzolo M, Pia A, Reimondo G. Subclinical cushing’s syndrome: definition and management. Clin Endocrinol. 2012;76(1):12–8.

    Article CAS Google Scholar

  33. Detomas M, Deutschbein T, Tamburello M, Chifu I, Kimpel O, Sbiera S et al. Erythropoiesis in Cushing syndrome: sex-related and subtype-specific differences. Results from a monocentric study. J Endocrinol Investig. 2023.

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Acknowledgements

The authors wish to thank the patients for their participation and kind cooperation.

Funding

The authors did not receive support from any organization for the submitted work.

Author information

Authors and Affiliations

  1. Endocrinology and Metabolism Research Center (EMRC), Vali-Asr Hospital, Tehran University of Medical Sciences, Tehran, Iran

    Mohammadali Tavakoli Ardakani, Soghra Rabizadeh, Amirhossein Yadegar, Fatemeh Mohammadi, Sahar Karimpour Reyhan, Reihane Qahremani, Alireza Esteghamati & Manouchehr Nakhjavani

  2. Advanced Diagnostic and Interventional Radiology Research Center (ADIR), Tehran University of Medical Sciences, Tehran, Iran

    Hossein Ghanaati

Contributions

MN and MTA and SR: Conception and design of the study. AY and FM and HG: Acquisition of data. MTA and AY and SR: Analysis and interpretation of data. FM and RQ and SK: Drafting the article. MN and AE and AY: Critical revision of the article. All authors read and approved the final manuscript.

Corresponding author

Correspondence to Manouchehr Nakhjavani.

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Ethics approval and consent to participate

This study was performed in line with the principles of the Declaration of Helsinki. Informed consent was obtained from all participants or their legal guardians. Approval was granted by the Research Ethics Committee of Tehran University of Medical Sciences (Approval number: IR.TUMS.MEDICINE.REC.1398.707).

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In order to publish this study, written informed consent was obtained from each participant. A copy of the written consent form is available for review by the journal editor.

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The authors declare no competing interests.

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Ardakani, M.T., Rabizadeh, S., Yadegar, A. et al. Bilateral inferior petrosal sinus sampling: validity, diagnostic accuracy in lateralization of pituitary microadenoma, and treatment in eleven patients with Cushing’s syndrome – a single-center retrospective cohort study. BMC Endocr Disord 23, 232 (2023). https://doi.org/10.1186/s12902-023-01495-z

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