Ectopic Adrenocorticotropic Hormone (ACTH)-Dependent Cushing Syndrome Secondary to Olfactory Neuroblastoma

Posted on September 15, 2025 by MaryO

Abstract

Background/Objective

Ectopic adrenocorticotropic hormone (ACTH)-dependent Cushing syndrome is a rare paraneoplastic disorder caused by excessive cortisol production from nonpituitary tumors. Olfactory neuroblastoma (ONB), a rare neuroendocrine malignancy of the sinonasal cavity, is an exceedingly uncommon source of ectopic ACTH production, with fewer than 25 cases reported worldwide. This report presents a case of ACTH-dependent Cushing syndrome due to ONB, emphasizing the diagnostic complexity, multidisciplinary management, and favorable clinical outcomes.

Case Presentation

A 70-year-old male presented with progressive muscle weakness, facial rounding, weight gain, hypertension, hypokalemia, and recurrent epistaxis. Laboratory evaluation revealed marked hypercortisolism and elevated plasma ACTH. Imaging demonstrated an expansile ethmoid sinus mass. Inferior petrosal sinus sampling excluded a pituitary source of ACTH. Endoscopic biopsy confirmed Hyams grade 2 ONB with positive immunohistochemical staining for neuroendocrine markers and ACTH. The patient received preoperative cortisol-lowering therapy and underwent complete endoscopic tumor resection followed by adjuvant radiotherapy. Postoperative assessment showed biochemical remission, resolution of Cushingoid features, and eventual recovery of the hypothalamic–pituitary–adrenal axis.

Discussion

This case highlights the importance of a systematic diagnostic approach that includes biochemical testing, imaging, inferior petrosal sinus sampling, and histopathology to identify ectopic ACTH sources. It demonstrates the necessity of collaboration among endocrinology, otolaryngology, neurosurgery, radiology, and oncology teams in managing rare ACTH-secreting tumors.

Conclusion

Timely diagnosis and definitive surgical resection of ACTH-producing ONB, along with endocrine stabilization and adjuvant radiotherapy, can lead to endocrine remission and improved long-term outcomes.

Key words

cushing syndrome
ectopic ACTH syndrome
neuroendocrine tumor
olfactory neuroblastoma
paraneoplastic syndrome

Abbreviations

ACTH

adrenocorticotropic hormone

AM

morning (ante meridiem)

DDAVP

desmopressin acetate

DHEA-S

dehydroepiandrosterone sulfate

EAS

ectopic ACTH syndrome

ENT

otolaryngology

IPSS

inferior petrosal sinus sampling

ONB

olfactory neuroblastoma

UFC

urinary free cortisol

Highlights

  • •
    Rare case of ectopic adrenocorticotropic hormone syndrome secondary to olfactory neuroblastoma
  • •
    Diagnostic challenges highlighted, including nondiagnostic inferior petrosal sinus sampling results
  • •
    Multidisciplinary approach enabled complete tumor resection and hormonal remission
  • •
    Preoperative ketoconazole minimized perioperative cortisol-related morbidity
  • •
    Adjuvant radiotherapy optimized local control in intermediate-risk olfactory neuroblastoma

Clinical Relevance

This case emphasizes the importance of recognizing olfactory neuroblastoma as a rare source of ectopic adrenocorticotropic hormone production. It demonstrates the value of integrated biochemical, radiologic, surgical, and histopathologic strategies to achieve endocrine remission and prevent recurrence.

Introduction

Ectopic ACTH syndrome (EAS) is a rare paraneoplastic disorder resulting in ACTH-dependent hypercortisolism, which manifests clinically as Cushing syndrome. Although it accounts for approximately 10% to 15% of ACTH-dependent cases, EAS is most frequently caused by bronchial carcinoids, small cell lung carcinoma, and pancreatic neuroendocrine tumors.1,2 In contrast, olfactory neuroblastoma (ONB), also known as esthesioneuroblastoma—a neuroendocrine malignancy of the upper nasal cavity—is a highly uncommon cause, with fewer than 1% of ONB cases associated with EAS.2,3
ONB arises from the olfactory epithelium and represents 2% to 3% of all sinonasal cancers.4,5 Its nonspecific presentation—ranging from nasal obstruction to epistaxis or anosmia—can delay diagnosis, and advanced tumors may invade adjacent structures such as the orbit or anterior cranial fossa.4,5 Histological overlap with other small round blue cell tumors necessitates immunohistochemical markers such as synaptophysin, chromogranin A, and S-100 for accurate identification.4,6 Factors such as age may influence tumor behavior, treatment selection, and prognosis.7
When ONB presents with ectopic ACTH secretion, the resulting hypercortisolism can lead to profound metabolic and cardiovascular complications.8,9 Due to its extreme rarity, this combination may not be initially suspected, delaying targeted therapy. This report presents a rare case of ACTH-dependent Cushing syndrome caused by ONB, highlighting the diagnostic complexity and need for multidisciplinary management.3,10

Case Presentation

A 70-year-old male presented with 6 weeks of progressively worsening generalized, proximal muscle weakness, intermittent headaches, recurrent nosebleeds, abdominal fullness, leg swelling, and an unexplained 20-pound (9.1 kg) weight gain.
His medical history includes asthma, benign prostatic hyperplasia, hyperlipidemia, and retained shrapnel in the neck from military service in Vietnam. He has no history of hypertension, diabetes, or smoking. His family history includes a father who suffered a myocardial infarction at 51 years old, a mother with rheumatoid arthritis and osteoporosis, and a maternal uncle with lupus. His current medications include rosuvastatin 5 mg daily, tamsulosin 0.4 mg daily, and an albuterol inhaler as needed.
On examination, his vital signs were notable for an elevated blood pressure of 171/84 mmHg (normal: <120/<80 mmHg), a temperature of 37.2 C (99 F) (normal: 36.1–37.2°C [97–99 F]), a heart rate of 91 bpm (normal: 60–100 bpm), a respiratory rate of 16 breaths per minute (normal: 12–20 breaths per minute), an oxygen saturation of 92% on room air (normal: ≥95%), and a weight of 78.9 kg (174 lb). Physical examination revealed a round plethoric face (“moon facies,”) a prominent dorsocervical fat pad (“buffalo hump,”) supraclavicular fullness, mild abdominal tenderness, violaceous striae across the abdomen, diffuse soft tissue swelling, and bilateral 2+ pitting edema in the lower extremities.

Diagnostic Assessment

Laboratory evaluation demonstrated severe hypokalemia (1.6 mEq/L [1.6 mmol/L]; normal: 3.5–5.0 mEq/L [3.5–5.0 mmol/L]) and marked fasting hyperglycemia (244.0 mg/dL [13.5 mmol/L]; normal: 70–99 mg/dL [3.9–5.5 mmol/L]), in addition to leukocytosis, hypochloremia, acute kidney injury, hypoproteinemia, and hypoalbuminemia.
Hormonal evaluation (Table 1) was consistent with ACTH-dependent hypercortisolism, characterized by elevated serum cortisol and ACTH concentrations, lack of suppression with dexamethasone, and suppressed dehydroepiandrosterone sulfate (DHEA-S). Aldosterone and plasma renin activity were within normal limits, effectively excluding primary hyperaldosteronism. Plasma free metanephrines and normetanephrines were also within reference ranges, ruling out pheochromocytoma. Repeat morning cortisol remained markedly elevated, and late-night salivary cortisol levels on 2 occasions were significantly above the reference range. Twenty-four-hour urinary free cortisol (UFC) was profoundly elevated on both collections. Following a 1 mg overnight dexamethasone suppression test, serum cortisol, ACTH, and dexamethasone levels confirmed a lack of cortisol suppression despite adequate dexamethasone absorption (Table 1). These results were consistent with ACTH-dependent Cushing syndrome.

Table 1. Hormone Panel Results

Test Value Normal Range
AM cortisol 29 μg/dL (800.11 nmol/L) (high) 3.7–19.4 μg/dL (102–535 nmol/L)
Repeated AM cortisol 26 μg/dL (717.34 nmol/L) (high) 3.7–19.4 μg/dL (102–535 nmol/L)
ACTH 250 pg/mL (30.03 pmol/L) (high) 10–60 pg/mL (2.2–13.2 pmol/L)
Plasma renin activity 1.2 ng/mL/h (1.2 μg/L/h) (normal) 0.2–4.0 ng/mL/h (0.2–4.0 μg/L/h)
DHEA-S 50 μg/dL (1.25 μmol/L) (low) 65–380 μg/dL (1.75–10.26 μmol/L)
Aldosterone, blood 4. 9 ng/dL (0.14 nmol/L) (normal) 4.0–31.0 ng/dL (110–860 pmol/L)
Plasma free metanephrines 0.34 nmol/L (0.034 μg/L) (normal) <0.50 nmol/L (<0.09 μg/L)
Plasma free normetanephrines 0.75 nmol/L (0.075 μg/L) (normal) <0.90 nmol/L (<0.16 μg/L)
Late-night salivary cortisol (1st) 0.27 μg/dL (7.45 nmol/L) (high) ≤0.09 μg/dL (≤2.5 nmol/L) (10 PM–1 AM)
Late-night salivary cortisol (2nd) 0.36 μg/dL (9.93 nmol/L) (high) ≤0.09 μg/dL (≤2.5 nmol/L) (10 PM–1 AM)
24-h urinary free cortisol (1st) 5880.0 μg/d (16 223 nmol/d) (high) ≤60.0 μg/d (≤165 nmol/d)
24-h urinary free cortisol (2nd) 4920.0 μg/d (13 576 nmol/d) (high) ≤60.0 μg/d (≤165 nmol/d)
AM cortisol level (after 1 mg dexamethasone) 12.3 μg/dL (339 nmol/L) (high) <1.8 μg/dL (<50 nmol/L) adequate suppression
Dexamethasone level(after 1 mg dexamethasone) 336 ng/dL (8.64 nmol/L) (normal) >200 ng/dL (>5.2 nmol/L) adequate absorption
ACTH level (after 1 mg dexamethasone) 242 pg/mL (53.27 pmol/L) (not suppressed) 10–60 pg/mL (2.2–13.2 pmol/L)
Abbreviations: μg/d = micrograms per day; μg/dL = Micrograms per deciliter; μg/L = micrograms per liter; μmol/L = micromoles per liter; AM = morning (Ante Meridiem); nmol/L = nanomoles per Liter; ng/mL/h = nanograms per milliliter per hour; pmol/L = picomoles per liter; pg/mL = picograms per milliliter; μg/L/h = micrograms per liter per hour; ng/dL = nanograms per deciliter; nmol/d = nanomoles per day.
Inferior petrosal sinus sampling (IPSS) was performed using contrast-enhanced fluoroscopy to confirm accurate catheter placement in both inferior petrosal sinuses. Absolute ACTH values obtained during IPSS are shown in (Table 2). The central-to-peripheral ACTH gradient at baseline was 1.1, which is below the diagnostic threshold of 2.0 typically required to support a pituitary source of ACTH. Following desmopressin acetate (DDAVP) stimulation, peak left: peripheral and right: peripheral ACTH ratios reached 1.7 and 1.5, respectively—well below the accepted post-stimulation cut-off of 3.0. In addition, the left: right petrosal ACTH ratios remained between 1.03 and 1.15 throughout the sampling period, indicating no significant lateralization of ACTH secretion. These findings are not consistent with Cushing’s disease and instead support a diagnosis of ectopic ACTH syndrome.

Table 2. Bilateral Petrosal Sinus and Peripheral Adrenocorticotropin Levels Before and After Intravenous Injection of Desmopressin Acetate (DDAVP) 10 mcg

Time post DDAVP, min Left petrosal ACTH Left: peripheral ACTH Right petrosal ACTH Right: peripheral ACTH Peripheral ACTH Left: right petrosal ACTH
0 165 pg/mL (36.3 pmol/L) 1.1 160 pg/mL (35.2 pmol/L) 1.1 150 pg/mL (33.0 pmol/L) 1.03
3 270 pg/mL (59.4 pmol/L) 1.6 245 pg/mL (53.9 pmol/L) 1.4 170 pg/mL (37.4 pmol/L) 1.10
5 320 pg/mL (70.4 pmol/L) 1.7 285 pg/mL (62.7 pmol/L) 1.5 185 pg/mL (40.7 pmol/L) 1.12
10 350 pg/mL (77.0 pmol/L) 1.4 305 pg/mL (67.2 pmol/L) 1.2 250 pg/mL (55.0 pmol/L) 1.15
Abbreviations: ACTH = adrenocorticotropin; DDAVP = desmopressin acetate; pg/mL = picograms per milliliter; pmol/L = picomoles per liter.
Magnetic resonance imaging of the head could not be performed due to a history of retained shrapnel in the neck from combat in Vietnam. Noncontrast computed tomography (CT) images of the head and paranasal sinuses revealed no evidence of a pituitary tumor but demonstrated an expansile mass measuring approximately 2.4 × 4.3 × 3.3 cm, centered within the bilateral ethmoid sinuses with extension into both the anterior and posterior ethmoidal air cells (Fig. 1A, B). A contrast-enhanced CT scan of the abdomen, performed following improvement in renal function, demonstrated marked bilateral adrenal gland enlargement (Fig. 1C).

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Fig. 1. (A) Axial and (B) coronal noncontrast computed tomography (CT) images of the head demonstrate a heterogeneous soft tissue mass at the anterior skull base extending toward the cribriform plate and into the right nasal cavity, involving the ethmoid sinus and eroding the lamina papyracea, resulting in medial displacement of the right orbital contents (blue arrows). (C) Axial contrast-enhanced CT of the abdomen reveals bilateral adrenal gland enlargement. (D) Whole-body single-photon emission computed tomography/computed tomography (SPECT/CT) using indium-111 pentetreotide demonstrates intense radiotracer uptake localized to the biopsy-confirmed esthesioneuroblastoma in the ethmoid sinuses, with no evidence of metastatic octreotide-avid lesions. (G) Coronal contrast-enhanced CT scan of the abdomen, performed after surgery, shows normalization in the size of both adrenal glands. (E) Coronal and (F) axial noncontrast CT images of the paranasal sinuses obtained postoperatively demonstrate complete surgical resection of the tumor.

The otolaryngology (ENT) team was consulted and recommended an endoscopic biopsy of the nasal mass. Histopathologic examination revealed a Hyams Grade 2 olfactory neuroblastoma (Fig. 2A, B), characterized by well-circumscribed lobules of small round blue cells with scant cytoplasm, a neurofibrillary background matrix, and low mitotic activity, without necrosis or rosette formation—findings typical of a moderately differentiated tumor in the Hyams grading system.

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Fig. 2. (A) Low-power H&E (4×) shows well-circumscribed lobules of small round blue cells with fibrovascular stroma and a neurofibrillary matrix; no necrosis or rosettes are seen. (B) High-power H&E (40×) reveals neoplastic cells with high nuclear-to-cytoplasmic ratio, hyperchromatic nuclei, and granular chromatin, consistent with Hyams Grade 2 ONB. (C) Chromogranin A shows granular cytoplasmic positivity in tumor nests, confirming neuroendocrine differentiation. (D) Synaptophysin shows diffuse granular cytoplasmic staining in tumor clusters, with negative stromal background. (E) S-100 highlights sustentacular cells in a peripheral pattern around tumor nests. (F) ACTH staining shows patchy to diffuse cytoplasmic positivity in tumor cells, confirming ectopic ACTH production in ONB. A nuclear medicine octreotide scan (111 Indium-pentetreotide scintigraphy) with single-photon emission computed tomography/computed tomography (SPECT/CT) demonstrated intense radiotracer uptake in the biopsy-proven esthesioneuroblastoma centered within the ethmoid sinuses, confirming the tumor’s expression of somatostatin receptors. There was no evidence of locoregional or distant metastatic disease demonstrating octreotide avidity (Fig. 1D).

Immunohistochemical staining supported the diagnosis: tumor cells were positive for chromogranin A (Fig. 2C), synaptophysin (Fig. 2D), and S-100 (Fig. 2E). Chromogranin A and synaptophysin are markers of neuroendocrine differentiation, confirming the tumor’s neuroendocrine origin. S-100 positivity in the sustentacular cells surrounding tumor nests is a classic feature of olfactory neuroblastoma. Staining was negative for neurofilament protein, AE1/AE3, and epithelial membrane antigen, helping exclude other small round blue cell tumors, such as neuroendocrine carcinoma or sinonasal undifferentiated carcinoma. Importantly, the tumor cells showed positive cytoplasmic staining for ACTH (Fig. 2F), confirming ectopic ACTH production by the tumor itself. This finding definitively links the olfactory neuroblastoma as the source of paraneoplastic ACTH secretion, consistent with the patient’s clinical picture of ectopic Cushing’s syndrome.

Treatment

Hypokalemia was corrected, and oral ketoconazole 200 mg twice daily was initiated preoperatively to mitigate the metabolic complications of hypercortisolism. Ketoconazole was discontinued on the day of surgery. The tumor was resected via an endoscopic endonasal approach. A blood sample was obtained immediately following tumor removal for measurement of ACTH and cortisol levels. Intravenous hydrocortisone (100 mg every 6 h) was initiated promptly thereafter. Postoperative cortisol and ACTH levels were undetectable: cortisol <5 μg/dL [<138 nmol/L] (normal: 5–25 μg/dL [138–690 nmol/L]); ACTH <5 pg/mL [<1.1 pmol/L] (normal: 10–60 pg/mL [2.2–13.3 pmol/L]). These findings confirmed successful surgical resection of the ACTH-secreting tumor. These issues extended the hospital stay and required treatment with antiseizure medications, antibiotics, and additional surgeries by ENT and Neurosurgery teams.

Outcome and Follow-Up

The patient demonstrated significant normalization of blood pressure (124/78 mmHg), fasting blood glucose (95 mg/dL [5.3 mmol/L]), and potassium (4.3 mEq/L [4.3 mmol/L]) within 2 weeks postoperatively. ACTH levels decreased from preoperative values of 220–250 pg/mL (48.4–55.2 pmol/L) to 29 pg/mL (5.5 pmol/L), and morning (AM) cortisol levels decreased from preoperative values of 29 μg/dL (800 nmol/L) to 12 μg/dL (331 nmol/L). These values were obtained at 2 weeks postoperatively. While early normalization of ACTH and cortisol levels could raise concern for residual disease, the patient’s subsequent sustained biochemical remission, clinical recovery, and a robust response to cosyntropin stimulation at 3 months post-op were reassuring. Adjuvant radiotherapy was also administered to mitigate any potential risk of recurrence.
He was subsequently transferred to an inpatient rehabilitation facility while receiving oral hydrocortisone replacement therapy, during which his functional status progressively improved. The patient was later discharged home on oral hydrocortisone replacement therapy with plans for continued outpatient physical therapy. Hydrocortisone was gradually tapered and discontinued 3 months after surgery, at which point blood pressure (122/76 mmHg), fasting glucose (90 mg/dL [5.0 mmol/L]), potassium (4.2 mEq/L [4.2 mmol/L]), ACTH (25 pg/mL [4.9 pmol/L]), and AM cortisol (15 μg/dL [414 nmol/L]) demonstrated sustained normalization. Following administration of 250 mcg intramuscular cosyntropin, serum cortisol peaked at 21 μg/dL (580 nmol/L), confirming an adequate adrenal reserve and complete recovery of the hypothalamic–pituitary–adrenal axis. Additionally, late-night salivary cortisol was remeasured on 2 occasions after hydrocortisone discontinuation and found to be 0.04 μg/dL (1.10 nmol/L) and 0.03 μg/dL (0.83 nmol/L), both within normal reference limits (≤0.09 μg/dL [≤2.5 nmol/L]). A 24-hour UFC collected at the same time measured 38 μg/d (105 nmol/d), confirming biochemical resolution of hypercortisolism. Cushing’s stigmata, including muscle weakness and skin changes, showed marked improvement by 3 months postoperatively (Table 3).

Table 3. Timeline of Clinical and Biochemical Recovery Following Resection of Ectopic ACTH-Secreting Olfactory Neuroblastoma

Parameter Preoperative value 24–48 h Postop 2 wks postop 3 mo postop Normal range
Blood pressure 171/84 mmHg 140/80 mmHg 124/78 mmHg 122/76 mmHg <130/80 mmHg
Fasting glucose 244 mg/dL (13.5 mmol/L) 160 mg/dL (8.9 mmol/L) 95 mg/dL (5.3 mmol/L) 90 mg/dL (5.0 mmol/L) 70–99 mg/dL (3.9–5.5 mmol/L)
Potassium 1.6 mEq/L (1.6 mmol/L) 3.8 mEq/L (3.8 mmol/L) 4.3 mEq/L (4.3 mmol/L) 4.2 mEq/L (4.2 mmol/L) 3.5–5.0 mEq/L (3.5–5.0 mmol/L)
ACTH 220–250 pg/mL (48.4–55.2 pmol/L) <10 pg/mL (<2.2 pmol/L) 29 pg/mL (5.5 pmol/L) 25 pg/mL (4.9 pmol/L) 10–60 pg/mL (2.2–13.3 pmol/L)
AM cortisol 29 μg/dL (800 nmol/L) <5 μg/dL (<138 nmol/L) 12 μg/dL (331 nmol/L) 15 μg/dL (414 nmol/L); Cosyntropin peak: 21 μg/dL (580 nmol/L) 5–25 μg/dL (138–690 nmol/L); adequate response >18 μg/dL (500–550 nmol/L)
LNSC 0.27/0.36 μg/dL (7.45/9.93 nmol/L) — — 0.04/0.03 μg/dL (1.10/0.83 nmol/L) ≤0.09 μg/dL (≤2.5 nmol/L) (10 PM–1 AM)
UFC (24-h) 5880/4920 μg/d (16 223/13 576 nmol/d) — — 38 μg/d (105 nmol/d) ≤60 μg/d (≤165 nmol/d)
Cushing’s Stigmata Moon facies, dorsocervical fat pad, violaceous striae, severe muscle weakness No change Partial improvement: BP/glucose control; decreased edema Marked improvement; muscle strength restored; striae fading Not applicable
Abbreviations: ACTH = adrenocorticotropin; mmHg = illimeters of mercury; mEq/L = milliequivalents per liter; mg/dL = milligrams per deciliter; mmol/L = millimoles per liter; μg/dL = micrograms per deciliter; AM = morning (Ante Meridiem); pg/mL = picograms per milliliter; pmol/L = picomoles per liter; nmol/L = nanomoles per liter.
dfA follow-up CT scan of the adrenals with contrast, performed following improvement in renal function, confirmed normalization in the size of the previously enlarged adrenal glands (Fig. 1E). A follow-up CT of sinuses without contrast confirmed complete resection of the tumor (Fig. 1F, G).
Adjuvant radiotherapy was recommended in view of the patient’s Kadish stage B tumor, Hyams grade 2 histology, and the elevated risk of local recurrence inherent to olfactory neuroblastoma. Despite complete surgical excision, radiotherapy was pursued to mitigate recurrence risk, particularly considering the tumor’s ectopic ACTH secretion, which suggested biologically aggressive behavior, as well as the patient’s satisfactory functional status and anticipated favorable treatment tolerance. A total of 30 fractions of 2 Gy were administered using volumetric modulated arc therapy.

Discussion

Diagnostic Considerations

EAS poses a significant diagnostic challenge due to its variable presentation and the urgency of identifying the source of ACTH excess. ONB, although rare, should be considered in patients with ACTH-dependent Cushing syndrome who present with sinonasal masses. ONB accounts for only 2% to 3% of all malignant sinonasal tumors,4,6 with fewer than 25 cases documented as sources of ectopic ACTH production.3,11,12
While ectopic ACTH syndrome remains the most well-recognized endocrine manifestation of ONB, a broader spectrum of paraneoplastic syndromes has also been described. These include syndrome of inappropriate antidiuretic hormone secretion, paraneoplastic hypercalcemia—often mediated by parathyroid hormone–related protein—and catecholamine excess mimicking pheochromocytoma.11 These atypical presentations underscore the neuroendocrine complexity of ONB and the diagnostic challenges they pose.
Diagnosis involves biochemical confirmation of hypercortisolism using low-dose dexamethasone suppression, 24-hour UFC, late-night salivary cortisol, and plasma ACTH levels. Interestingly, despite markedly elevated ACTH levels, our patient exhibited a low DHEA-S concentration and a normal aldosterone level. This biochemical pattern supports previous observations that EAS may present with a dissociation in adrenal steroidogenesis. Chronic hypercortisolemia may suppress the zona reticularis,13 while ectopic ACTH-producing tumors may secrete aberrant precursors that preferentially stimulate glucocorticoid rather than androgen synthesis.14 Cortisol excess can also downregulate key enzymes such as 17,20-lyase and SULT2A1, thereby impairing DHEA-S production.15 Moreover, the rapid onset and severity of ectopic ACTH production may preclude the compensatory DHEA-S rise typically observed in pituitary-driven Cushing disease. Although cortisol excess is known to suppress the renin-angiotensin-aldosterone system, aldosterone levels may remain detectable in certain EAS cases, particularly in early-stage or physiologically variable presentations.16
Once ACTH-dependence is established, localization of the tumor becomes essential. IPSS, although considered the gold standard for distinguishing pituitary from ectopic ACTH sources, may yield inconclusive results in cases of ONB due to altered venous drainage pathways.3 Functional imaging with 111In-octreotide single-photon emission computed tomography/computed tomography or 68Ga-DOTATATE positron emission tomography/computed tomography facilitates localization of neuroendocrine tumors that express somatostatin receptors. Histopathologic confirmation using ACTH immunostaining and neuroendocrine markers such as chromogranin A, synaptophysin, and S-100 is essential to confirm diagnosis.

Therapeutic Approach and Challenges

Surgical resection remains the cornerstone of management for ACTH-producing ONB.9 Endoscopic endonasal approaches are preferred when anatomically feasible due to their minimally invasive nature and favorable access to the anterior skull base. Preoperative pharmacologic inhibition of cortisol biosynthesis (utilizing ketoconazole, which was specifically selected for our patient, metyrapone, or etomidate) represents a critical intervention to attenuate hypercortisolism-related metabolic complications and minimize perioperative morbidity.3,8 Intraoperative glucocorticoid replacement should be administered following tumor resection to prevent adrenal insufficiency. Postoperative complications—such as cerebrospinal fluid leak or infection—require prompt multidisciplinary intervention.
Adjuvant radiotherapy is generally recommended for intermediate-to high-grade ONBs, even after gross total resection, given their aggressive behavior and high risk of recurrence. Volumetric modulated arc therapy delivers precise radiation doses while minimizing toxicity to adjacent structures.5,9 Platinum-based chemotherapy remains a therapeutic option in patients with unresectable or metastatic disease.9
Emerging therapeutic strategies include somatostatin receptor–directed theranostics. Zhi et al (2025) recently demonstrated the dual diagnostic and therapeutic potential of 68Ga-DOTATATE positron emission tomography/computed tomography imaging and 177Lu-DOTATATE peptide receptor radionuclide therapy in ONB, offering promising future directions for patients with advanced or somatostatin receptor–positive disease.17

Prognosis and Future Directions

The prognosis of ONB is influenced by Kadish staging, Hyams histologic grading, and treatment strategy. Recurrence rates are reported to range from 30% to 60%,9,18 and 5-year survival rates vary from 45% to 80% depending on tumor grade, stage, and completeness of resection.6,19 Early detection, complete surgical resection, and multimodal therapy, including radiotherapy, are associated with improved outcomes. Lifelong follow-up with serial imaging and endocrine evaluation is essential to monitor for recurrence and late-onset adrenal insufficiency.10,19
Continued advancements in molecular imaging and targeted therapies, particularly those leveraging somatostatin receptor biology, may expand the therapeutic landscape for patients with recurrent or progressive ONB.

Conclusion

This case highlights the importance of timely diagnosis, comprehensive biochemical and radiologic assessment, and coordinated multidisciplinary management in ACTH-producing ONB. In addition to surgery and preoperative endocrine stabilization, adjuvant radiotherapy and long-term surveillance are critical components of care. As somatostatin receptor–based imaging and theranostic therapies evolve, they offer exciting opportunities to individualize treatment in this rare but challenging neuroendocrine malignancy.

Statement of Patient Consent

Written informed consent was obtained from the patient for publication of this case report and any accompanying images.

Disclosure

The author has no conflict of interest to disclose.

References

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Thin Skin in Cushing’s Syndrome

Posted on March 23, 2025 by MaryO

Abstract

A 53-year-old woman with a history of metastatic small-cell lung cancer was evaluated during an inpatient admission for Cushing’s syndrome on the basis of new findings of hypertension, hypokalemia, hyperglycemia, and metabolic alkalosis.
A focused physical examination was performed to assess for the antianabolic effects of excess cortisol. The thickness of the skin on the back of her third finger was 1.2 mm (reference value, >1.8) when measured with skin calipers (Panels A and B). Thin skin — a clinical sign strongly suggestive of hypercortisolism — results from inhibition of collagen synthesis by glucocorticoids.
To avoid interference from subcutaneous fat, skin thickness should be measured on the backs of the fingers. The measurement can be done with skin calipers (see Video 1) or electrocardiogram calipers (see Video 2). Levels of random plasma cortisol, midnight plasma cortisol, 24-hour urine cortisol, and corticotropin were elevated.
Magnetic resonance imaging of the brain showed no pituitary abnormalities. Whole-body restaging imaging showed new metastatic lesions in the lungs, bones, liver, and meninges. A diagnosis of Cushing’s syndrome — presumed to be paraneoplastic — was made.
After discussing her prognosis with her physicians, the patient opted for palliative care and died 1 week later.

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Atypical Presentation of Cushing’s Disease With Weight Loss and Hypokalemia

Posted on October 29, 2024 by MaryO

Abstract

Summary

ACTH-secreting pituitary adenomas causing Cushing’s disease (CD) typically present with weight gain, whereas weight loss and hypokalemia in endogenous Cushing’s patients are suggestive of ectopic ACTH production. We report a case of CD presenting with atypical features of marked weight loss and hypokalemia. A 75-year-old female was admitted to the hospital with a history of profound weight loss, associated with uncontrolled hypertension, hyperglycemia, severe proximal muscle weakness, and hypokalemia. Subsequent investigations, including 24-h urinary free cortisol, 48-h low-dose dexamethasone suppression test, MRI of the sella, and bilateral inferior petrosal sinus sampling, confirmed CD without any evidence of ectopic ACTH production. She became eucortisolemic with medical therapy of ketoconazole and cabergoline, subsequently regained her weight, and became normokalemic. This case illustrates that patients with CD may present with symptoms and biochemical findings that would otherwise suggest ectopic ACTH production.

Learning points

  • Patients with CD do not always present with classical clinical features and may present with symptoms and biochemical findings that would otherwise suggest ectopic ACTH production.
  • While most patients with CD typically lose weight after biochemical remission, some patients gain weight after the normalization of cortisol levels.
  • This case highlights the need to entertain a broad differential in patients presenting with hypokalemia and weight loss and the need to exclude hypercortisolemia.

Background

Pituitary corticotropin (ACTH)-induced Cushing’s disease (CD) accounts for approximately 70% of patients presenting with Cushing’s syndrome (1). ACTH-producing pituitary adenomas are typically microadenomas and, in over a third of CD patients, there is no demonstrable lesion on MRI (2). Clinical and biochemical diagnosis of CD may be challenging, as patients can present with varied symptoms that overlap with other comorbidities. Progressive weight gain associated with central adiposity is a common manifestation of CD occurring during the early stage of the disease. While nonspecific features such as hypertension, diabetes, cardiac hypertrophy, arterial and venous thrombosis, electrolyte abnormalities, and psychiatric disturbances also occur frequently, the more discriminatory signs of hypercortisolemia include proximal myopathy, facial plethora, easy bruising, and wide striae (2). Weight loss with associated hypokalemia typically suggests an underlying ectopic ACTH production. Here we report an unusual case of pituitary ACTH-induced CD who presented with significant hypokalemia and marked weight loss which resolved with medical control of CD.

Case presentation

A 75-year-old female with a history of type 2 diabetes, hypertension, osteoporosis, and coronary artery disease presented to the emergency department (ED) with profound proximal muscle weakness associated with a serum potassium of 2.4 mmol/L (normal = 3.6–5.2 mmol/L). She also reported a weight loss of 90 lbs over the previous 2 years. In addition, she had uncontrolled hypertension despite taking three anti-hypertensive agents and worsening glycemic control requiring increasing anti-hyperglycemic therapy; her hemoglobin A1c at presentation was 9.3%.

Investigation

During hospitalization, she underwent further investigation for hypokalaemia and resistant hypertension, which showed an elevated 24-h urine free cortisol (24-h UFC) of 1904.4 nmol/d (upper limit of normal: 485.4 nmol/d) and consequently was referred to Endocrinology for further assessment. Repeat outpatient-based investigations after discharge from the hospital confirmed an elevated 24-h UFC of 1578.4 nmol/d, elevated AM serum cortisol of 1749.2 nmol/L (normal: 80–477.3 nmol/L), non-suppressed serum cortisol of 1238.8 nmol/L (normal response: < 50 nmol/L) after a 48-h low dose dexamethasone suppression test, and an elevated serum ACTH at 8.2 pmol/L (normal: 0.5–2.2 pmol/L). MRI of the sella as well as gallium DOTATATE PET-CT did not show any demonstrable lesion (Figs 1A, B and 2A, B). Subsequently, she underwent bilateral inferior petrosal sinus sampling (BIPSS) using 100 µg ovine CRH, which showed a post-CRH central to peripheral ACTH ratio of 3, lateralizing to the right with a ratio of 2.1. Based on these findings, a diagnosis of MRI-negative CD was made.

Figure 1View Full Size
Figure 1
(A and B) MRI Sella post-GAD coronal and sagittal sections showing no pituitary lesion.

Citation: Endocrinology, Diabetes & Metabolism Case Reports 2024, 3; 10.1530/EDM-24-0011

Figure 2View Full Size
Figure 2
(A and B) Ga68 DOTATATE scan. PET-CT showing non-specific uptake through the distal esophagus and proximal stomach, but otherwise within normal physiological limits.

Citation: Endocrinology, Diabetes & Metabolism Case Reports 2024, 3; 10.1530/EDM-24-0011

Treatment

While awaiting surgical opinion, the patient was started on Ketoconazole 200 mg po TID. She was unable to tolerate a larger dose; therefore, cabergoline 1 mg twice a week was added. The options of trans-sphenoidal pituitary surgery and bilateral adrenalectomy were discussed with the patient, which she declined, and decided to continue with medical therapy.

Outcome and follow-up

Medical therapy was adjusted over the next several weeks until 24-h UFC normalized and remained normal during 24 months of follow-up with the most recent being 85 nmol/d. With biochemical remission of CD, her blood pressure normalized, and she required a reduction in the dose of anti-hypertensive and anti-hyperglycaemic therapy. Her serum potassium levels also normalized. She initially regained 15 lbs but called the clinic when, despite taking medical therapy, she once again began losing weight and her serum potassium dropped to 2.7 mmol/L. Repeat serum AM cortisol was significantly elevated at 935.3 nmol/L, as was 24h UFC at 1457.3 nmol/d. Further inquiry revealed that she had been prescribed omeprazole therapy by her family physician for symptoms of reflux. Omeprazole was discontinued due to its potential effect on decreasing the efficacy of ketoconazole therapy, and her cortisol and potassium levels rapidly normalized. Since then, she has regained 50 lbs, being almost back to her baseline weight, and her mobility and strength have improved from being initially bed-bound to now mobilizing independently using a walker. Pre and post therapy values are summarized in Table 1.

Table 1Key investigations at presentation and recent follow-up visit.

Test Reference range At presentation Recent follow-up
24-h urine cortisol (nmol/TV) ULN=486 1908  85
AM cortisol (nmol/L) 133-537 2371 796
Cortisol post-48h low DMS dose (nmol/L) <1.8 44.9 NA
ACTH (pmol/L) 2.3-10.1 37.5 14
Potassium (mmol/L) 3.6-5.2  2.4 4.5

DMS= dexamethasone suppression; NA = Not Applicable; ULN = upper limit of normal.

Discussion

Here we report an unusual case of CD presenting with features that were initially highly suggestive of ectopic ACTH production with weight loss rather than the usual weight gain. All of the initial symptoms resolved following biochemical control of hypercortisolemia. In our review of the literature, CD associated with weight loss has previously only been reported in association with severe depression, psychosis, eating disorders, or malignancy (3, 4). For instance, a case of familial CD was reported in a child who also had an intercurrent eating disorder (anorexia), which led to weight loss despite CD (3). Weight loss due to ectopic ACTH-induced CD has also been previously reported, where weight loss was thought to be due to the underlying malignancy (4). However, our patient had well-documented pituitary ACTH-induced CD.

Chronic hypercortisolemia is associated with increased abdominal adiposity that is thought to be caused by the downregulation of adenosine monophosphate-activated protein kinase (AMPK), which is responsible for regulating lipid metabolism (5). Furthermore, glucocorticoids also induce a direct orexigenic effect, which leads to weight gain (6). Weight loss in association with hypercortisolemia, on the contrary, can be a presenting feature of ectopic ACTH-producing tumors such as small cell lung cancer. While the underlying mechanism of weight loss is not fully understood, it is thought to be partly due to cAMP/Protein kinase A (PKA) pathway activation, with an increase in PKA activity resulting in altered downstream regulation of cAMP-related lipogenic and lipolytic proteins (6). In addition, high ACTH secretion and the malignant characteristics of the neoplastic process are also thought to play roles in weight loss (7). Our patient had no evidence of ectopic ACTH production.

A previous study (8) comparing the clinical features of CD in older vs younger patients reported that weight gain was more common in younger individuals, whereas older patients typically presented with catabolic changes, likely due to age-related variability in tissue sensitivity to glucocorticoid receptors and intracellular cortisol signaling. The overall rates of central adiposity were 71.1% in older patients compared with 80.0% in younger patients (8).

Another unusual feature was hypokalemia, which is generally associated with ectopic ACTH production. However, up to 10% of CD patients present with low potassium. Hypokalemia is caused by the mineralocorticoid effect of excess cortisol. Supraphysiologic production of cortisol tends to saturate 11β-hydroxysteroid dehydrogenase type II (11β-HSD2) activity in the renal tubule, which is primarily responsible for converting active cortisol into inactive cortisone. This could lead to excess binding of cortisol to mineralocorticoid receptors, resulting in an increase in potassium excretion and thus hypokalemia. While some studies have suggested that ACTH can also lead to lowering 11β-HSD2 activity causing hypokalemia, others have not found any such correlation (9, 10). In our patient, serum potassium normalized after she achieved eucortisolemia with medical therapy.

Declaration of interest

The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the study reported.

Funding

This research did not receive any specific grant from any funding agency in the public, commercial, or not-for-profit sector.

Patient consent

Written informed consent for publication of their clinical details and/or clinical images was obtained from the patient/parent/guardian/relative of the patient.

Author contribution statement

All authors reviewed the results and approved the final version of the manuscript.

Acknowledgements

We thank Dr Brian Moses (Yarmouth Regional Hospital, NS, Canada) and Dr Scott Lee (Valley Regional Hospital, NS, Canada) for their contributions in managing the patient.

References

Filed under: Cushing's, symptoms | Tagged: , , | Leave a comment »

Unveiling the Uncommon: Cushing’s Syndrome (CS) Masquerading as Severe Hypokalemia

Posted on July 2, 2024 by MaryO

Abstract

Cushing’s syndrome (CS) arises from an excess of endogenous or exogenous cortisol, with Cushing’s disease specifically implicating a pituitary adenoma and exaggerated adrenocorticotropic hormone (ACTH) production. Typically, Cushing’s disease presents with characteristic symptoms such as weight gain, central obesity, moon face, and buffalo hump.

This case report presents an unusual manifestation of CS in a 48-year-old male with a history of hypertension, where severe hypokalemia was the primary presentation. Initial complaints included bilateral leg swelling, muscle weakness, occasional shortness of breath, and a general feeling of not feeling well. Subsequent investigations revealed hypokalemia, metabolic alkalosis, and an abnormal response to dexamethasone suppression, raising concerns about hypercortisolism. Further tests, including 24-hour urinary free cortisol and ACTH testing, confirmed significant elevations. Brain magnetic resonance imaging (MRI) identified a pituitary macroadenoma, necessitating neurosurgical intervention.

This case underscores the rarity of CS presenting with severe hypokalemia, highlighting the diagnostic challenges and the crucial role of a collaborative approach in managing such intricate cases.

Introduction

Cushing’s syndrome (CS), characterized by excessive cortisol production, is well-known for its diverse and often conspicuous clinical manifestations. Cushing’s disease is a subset of CS resulting from a pituitary adenoma overproducing adrenocorticotropic hormone (ACTH), leading to heightened cortisol secretion. The classic presentation involves a spectrum of symptoms such as weight gain, central obesity, muscle weakness, and mood alterations [1].

Despite its classic presentation, CS can demonstrate diverse and atypical features, challenging conventional diagnostic paradigms. This case report sheds light on a rare manifestation of CS, where severe hypokalemia was the primary clinical indicator. Notably, instances of CS prominently manifesting through severe hypokalemia are scarce in the literature [1,2].

Through this exploration, we aim to provide valuable insights into the diagnostic intricacies of atypical CS presentations, underscore the significance of a comprehensive workup, and emphasize the collaborative approach essential for managing such uncommon hormonal disorders.

Case Presentation

A 48-year-old male with a history of hypertension presented to his primary care physician with complaints of bilateral leg swelling, occasional shortness of breath, dizziness, and a general feeling of malaise persisting for 10 days. The patient reported increased water intake and urinary frequency without dysuria. The patient was diagnosed with hypertension eight months ago. He experienced progressive muscle weakness over two months, hindering his ability to perform daily activities, including using the bathroom. The primary care physician initiated a blood workup that revealed severe hypokalemia with a potassium level of 1.3 mmol/L (reference range: 3.6 to 5.2 mmol/L), prompting referral to the hospital.

Upon admission, the patient was hypertensive with a blood pressure of 180/103 mmHg, a heart rate of 71 beats/minute, a respiratory rate of 18 breaths/minute, and an oxygen saturation of 96% on room air. Physical examination revealed fine tremors, bilateral 2+ pitting edema in the lower extremities up to mid-shin, abdominal distension with normal bowel sounds, and bilateral reduced air entry in the bases of the lungs on auscultation. The blood work showed the following findings (Table 1).

Parameter Result Reference Range
Potassium (K) 1.8 mmol/L 3.5-5.0 mmol/L
Sodium (Na) 144 mmol/L 135-145 mmol/L
Magnesium (Mg) 1.3 mg/dL 1.7-2.2 mg/dL
Hemoglobin (Hb) 15.5 g/dL 13.8-17.2 g/dL
White blood cell count (WBC) 13,000 x 103/µL 4.5 to 11.0 × 109/L
Platelets 131,000 x 109/L 150-450 x 109/L
pH 7.57 7.35-7.45
Bicarbonate (HCO3) 46 mmol/L 22-26 mmol/L
Lactic acid 4.2 mmol/L 0.5-2.0 mmol/L
Table 1: Blood work findings

In order to correct the electrolyte imbalances, the patient received intravenous (IV) magnesium and potassium replacement and was later transitioned to oral. The patient was also started on normal saline at 100 cc per hour. To further investigate the complaint of shortness of breath, the patient underwent a chest X-ray, which revealed bilateral multilobar pneumonia (Figure 1). He was subsequently treated with ceftriaxone (1 g IV daily) and clarithromycin (500 mg twice daily) for seven days.

A-chest-X-ray-revealing-(arrows)-bilateral-multilobar-pneumonia
Figure 1: A chest X-ray revealing (arrows) bilateral multilobar pneumonia

With persistent abdominal pain and lactic acidosis, a computed tomography (CT) scan abdomen and pelvis with contrast was conducted, revealing a psoas muscle hematoma. Subsequent magnetic resonance imaging (MRI) depicted an 8×8 cm hematoma involving the left psoas and iliacus muscles. The interventional radiologist performed drainage of the hematoma involving the left psoas and iliacus muscles (Figure 2).

Magnetic-resonance-imaging-(MRI)-depicting-an-8x8-cm-hematoma-(arrow)-involving-the-left-psoas-and-iliacus-muscles
Figure 2: Magnetic resonance imaging (MRI) depicting an 8×8 cm hematoma (arrow) involving the left psoas and iliacus muscles

In light of the concurrent presence of hypokalemia, hypertension, and metabolic alkalosis, there arose concerns about Conn’s syndrome, prompting consultation with endocrinology. Their recommended workup for Conn’s syndrome included assessments of the aldosterone-renin ratio and random cortisol levels. The results unveiled an aldosterone level below 60 pmol/L (reference range: 190 to 830 pmol/L in SI units) and a plasma renin level of 0.2 pmol/L (reference range: 0.7 to 3.3 mcg/L/hr in SI units). Notably, the aldosterone-renin ratio was low, conclusively ruling out Conn’s syndrome. The random cortisol level was notably elevated at 1334 nmol/L (reference range: 140 to 690 nmol/L).

Furthermore, a low-dose dexamethasone suppression test was undertaken due to the high cortisol levels. Following the administration of 1 mg of dexamethasone at 10 p.m., cortisol levels were measured at 9 p.m., 3 a.m., and 9 a.m. the following day. The results unveiled a persistently elevated cortisol level surpassing 1655 nmol/L, signaling an abnormal response to dexamethasone suppression and raising concerns about a hypercortisolism disorder, such as CS.

In the intricate progression of this case, the investigation delved deeper with a 24-hour urinary free cortisol level, revealing a significant elevation at 521 mcg/day (reference range: 10 to 55 mcg/day). Subsequent testing of ACTH portrayed a markedly elevated level of 445 ng/L, distinctly exceeding the normal reference range of 7.2 to 63.3 ng/L. A high-dose 8 mg dexamethasone test was performed to ascertain the source of excess ACTH production. The baseline serum cortisol levels before the high-dose dexamethasone suppression test were 1404 nmol/L, which decreased to 612 nmol/L afterward, strongly suggesting the source of excess ACTH production to be in the pituitary gland.

A CT scan of the adrenal glands ruled out adrenal mass, while an MRI of the brain uncovered a 1.3×1.3×3.2 cm pituitary macroadenoma (Figure 3), leading to compression of adjacent structures. Neurosurgery was consulted, and they recommended surgical removal of the macroadenoma due to the tumor size and potential complications. The patient was referred to a tertiary care hospital for pituitary adenoma removal.

Magnetic-resonance-imaging-(MRI)-of-the-brain-depicting-a-1.3x1.3x3.2-cm-pituitary-macroadenoma-(star)
Figure 3: Magnetic resonance imaging (MRI) of the brain depicting a 1.3×1.3×3.2 cm pituitary macroadenoma (star)

Discussion

CS represents a complex endocrine disorder characterized by excessive cortisol production. While the classic presentation of CS includes weight gain, central obesity, and muscle weakness, our case highlights an uncommon initial manifestation: severe hypokalemia. This atypical presentation underscores the diverse clinical spectrum of CS and the challenges it poses in diagnosis and management [1,2].

While CS typically presents with the classic symptoms mentioned above, severe hypokalemia as the initial manifestation is exceedingly rare. Hypokalemia in CS often results from excess cortisol-mediated activation of mineralocorticoid receptors, leading to increased urinary potassium excretion and renal potassium wasting. Additionally, metabolic alkalosis secondary to cortisol excess further exacerbates hypokalemia [3,4].

Diagnosing a case of Cushing’s disease typically commences with a thorough examination of the patient’s medical history and a comprehensive physical assessment aimed at identifying characteristic manifestations such as central obesity, facial rounding, proximal muscle weakness, and increased susceptibility to bruising. Essential to confirming the diagnosis are laboratory examinations, which involve measuring cortisol levels through various tests, including 24-hour urinary free cortisol testing, late-night salivary cortisol testing, and dexamethasone suppression tests. Furthermore, assessing plasma ACTH levels aids in distinguishing between pituitary-dependent and non-pituitary causes of CS. Integral to the diagnostic process are imaging modalities such as MRI of the pituitary gland, which facilitate the visualization of adenomas and the determination of their size and precise location [1-4].

Treatment for Cushing’s disease primarily entails surgical removal of the pituitary adenoma via transsphenoidal surgery, with the aim of excising the tumor and restoring normal pituitary function. In cases where surgical intervention is unsuitable or unsuccessful, pharmacological therapies employing medications such as cabergoline (a dopamine receptor agonist) or pasireotide (a somatostatin analogue) may be considered to suppress ACTH secretion and regulate cortisol levels. Additionally, radiation therapy, whether conventional or stereotactic radiosurgery, serves as a supplementary or alternative treatment approach to reduce tumor dimensions and mitigate ACTH production [5,6]. To assess the effectiveness of treatment, manage any problem, and assure long-term illness remission, diligent long-term follow-up and monitoring are essential. Collaborative multidisciplinary care involving specialists such as endocrinologists, neurosurgeons, and other healthcare professionals is pivotal in optimizing patient outcomes and enhancing overall quality of life [2,4].

The prognosis of CS largely depends on the underlying cause, stage of the disease, and efficacy of treatment. Early recognition and prompt intervention are essential for improving outcomes and minimizing long-term complications. Surgical resection of the adrenal or pituitary tumor can lead to remission of CS in the majority of cases. However, recurrence rates vary depending on factors such as tumor size, invasiveness, and completeness of resection [2,3]. Long-term follow-up with endocrinologists is crucial for monitoring disease recurrence, assessing hormonal function, and managing comorbidities associated with CS.

Conclusions

In conclusion, our case report highlights the rarity of severe hypokalemia as the initial presentation of CS. This unique presentation underscores the diverse clinical manifestations of CS and emphasizes the diagnostic challenges encountered in clinical practice. A multidisciplinary approach involving endocrinologists, neurosurgeons, and radiologists is essential for the timely diagnosis and management of CS. Early recognition, prompt intervention, and long-term follow-up are essential for optimizing outcomes and improving the quality of life for patients with this endocrine disorder.

References

  1. Nieman LK, Biller BM, Findling JW, Newell-Price J, Savage MO, Stewart PM, Montori VM: The diagnosis of Cushing’s syndrome: an Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2008, 93:1526-40. 10.1210/jc.2008-0125
  2. Newell-Price J, Bertagna X, Grossman AB, Nieman LK: Cushing’s syndrome. Lancet. 2006, 367:1605-17. 10.1016/S0140-6736(06)68699-6
  3. Torpy DJ, Mullen N, Ilias I, Nieman LK: Association of hypertension and hypokalemia with Cushing’s syndrome caused by ectopic ACTH secretion: a series of 58 cases. Ann N Y Acad Sci. 2002, 970:134-44. 10.1111/j.1749-6632.2002.tb04419.x
  4. Elias C, Oliveira D, Silva MM, Lourenço P: Cushing’s syndrome behind hypokalemia and severe infection: a case report. Cureus. 2022, 14:e32486. 10.7759/cureus.32486
  5. Fleseriu M, Petersenn S: Medical therapy for Cushing’s disease: adrenal steroidogenesis inhibitors and glucocorticoid receptor blockers. Pituitary. 2015, 18:245-52. 10.1007/s11102-014-0627-0
  6. Pivonello R, De Leo M, Cozzolino A, Colao A: The treatment of Cushing’s disease. Endocr Rev. 2015, 36:385-486. 10.1210/er.2013-1048

Filed under: Cushing's, pituitary, symptoms | Tagged: , , , , , , , , | Leave a comment »

Unveiling the Uncommon: Cushing’s Syndrome (CS) Masquerading as Severe Hypokalemia

Posted on April 26, 2024 by MaryO

Abstract

Cushing’s syndrome (CS) arises from an excess of endogenous or exogenous cortisol, with Cushing’s disease specifically implicating a pituitary adenoma and exaggerated adrenocorticotropic hormone (ACTH) production. Typically, Cushing’s disease presents with characteristic symptoms such as weight gain, central obesity, moon face, and buffalo hump.

This case report presents an unusual manifestation of CS in a 48-year-old male with a history of hypertension, where severe hypokalemia was the primary presentation. Initial complaints included bilateral leg swelling, muscle weakness, occasional shortness of breath, and a general feeling of not feeling well. Subsequent investigations revealed hypokalemia, metabolic alkalosis, and an abnormal response to dexamethasone suppression, raising concerns about hypercortisolism. Further tests, including 24-hour urinary free cortisol and ACTH testing, confirmed significant elevations. Brain magnetic resonance imaging (MRI) identified a pituitary macroadenoma, necessitating neurosurgical intervention.

This case underscores the rarity of CS presenting with severe hypokalemia, highlighting the diagnostic challenges and the crucial role of a collaborative approach in managing such intricate cases.

Introduction

Cushing’s syndrome (CS), characterized by excessive cortisol production, is well-known for its diverse and often conspicuous clinical manifestations. Cushing’s disease is a subset of CS resulting from a pituitary adenoma overproducing adrenocorticotropic hormone (ACTH), leading to heightened cortisol secretion. The classic presentation involves a spectrum of symptoms such as weight gain, central obesity, muscle weakness, and mood alterations [1].

Despite its classic presentation, CS can demonstrate diverse and atypical features, challenging conventional diagnostic paradigms. This case report sheds light on a rare manifestation of CS, where severe hypokalemia was the primary clinical indicator. Notably, instances of CS prominently manifesting through severe hypokalemia are scarce in the literature [1,2].

Through this exploration, we aim to provide valuable insights into the diagnostic intricacies of atypical CS presentations, underscore the significance of a comprehensive workup, and emphasize the collaborative approach essential for managing such uncommon hormonal disorders.

Case Presentation

A 48-year-old male with a history of hypertension presented to his primary care physician with complaints of bilateral leg swelling, occasional shortness of breath, dizziness, and a general feeling of malaise persisting for 10 days. The patient reported increased water intake and urinary frequency without dysuria. The patient was diagnosed with hypertension eight months ago. He experienced progressive muscle weakness over two months, hindering his ability to perform daily activities, including using the bathroom. The primary care physician initiated a blood workup that revealed severe hypokalemia with a potassium level of 1.3 mmol/L (reference range: 3.6 to 5.2 mmol/L), prompting referral to the hospital.

Upon admission, the patient was hypertensive with a blood pressure of 180/103 mmHg, a heart rate of 71 beats/minute, a respiratory rate of 18 breaths/minute, and an oxygen saturation of 96% on room air. Physical examination revealed fine tremors, bilateral 2+ pitting edema in the lower extremities up to mid-shin, abdominal distension with normal bowel sounds, and bilateral reduced air entry in the bases of the lungs on auscultation. The blood work showed the following findings (Table 1).

Parameter Result Reference Range
Potassium (K) 1.8 mmol/L 3.5-5.0 mmol/L
Sodium (Na) 144 mmol/L 135-145 mmol/L
Magnesium (Mg) 1.3 mg/dL 1.7-2.2 mg/dL
Hemoglobin (Hb) 15.5 g/dL 13.8-17.2 g/dL
White blood cell count (WBC) 13,000 x 103/µL 4.5 to 11.0 × 109/L
Platelets 131,000 x 109/L 150-450 x 109/L
pH 7.57 7.35-7.45
Bicarbonate (HCO3) 46 mmol/L 22-26 mmol/L
Lactic acid 4.2 mmol/L 0.5-2.0 mmol/L
Table 1: Blood work findings

In order to correct the electrolyte imbalances, the patient received intravenous (IV) magnesium and potassium replacement and was later transitioned to oral. The patient was also started on normal saline at 100 cc per hour. To further investigate the complaint of shortness of breath, the patient underwent a chest X-ray, which revealed bilateral multilobar pneumonia (Figure 1). He was subsequently treated with ceftriaxone (1 g IV daily) and clarithromycin (500 mg twice daily) for seven days.

A-chest-X-ray-revealing-(arrows)-bilateral-multilobar-pneumonia
Figure 1: A chest X-ray revealing (arrows) bilateral multilobar pneumonia

With persistent abdominal pain and lactic acidosis, a computed tomography (CT) scan abdomen and pelvis with contrast was conducted, revealing a psoas muscle hematoma. Subsequent magnetic resonance imaging (MRI) depicted an 8×8 cm hematoma involving the left psoas and iliacus muscles. The interventional radiologist performed drainage of the hematoma involving the left psoas and iliacus muscles (Figure 2).

Magnetic-resonance-imaging-(MRI)-depicting-an-8x8-cm-hematoma-(arrow)-involving-the-left-psoas-and-iliacus-muscles
Figure 2: Magnetic resonance imaging (MRI) depicting an 8×8 cm hematoma (arrow) involving the left psoas and iliacus muscles

In light of the concurrent presence of hypokalemia, hypertension, and metabolic alkalosis, there arose concerns about Conn’s syndrome, prompting consultation with endocrinology. Their recommended workup for Conn’s syndrome included assessments of the aldosterone-renin ratio and random cortisol levels. The results unveiled an aldosterone level below 60 pmol/L (reference range: 190 to 830 pmol/L in SI units) and a plasma renin level of 0.2 pmol/L (reference range: 0.7 to 3.3 mcg/L/hr in SI units). Notably, the aldosterone-renin ratio was low, conclusively ruling out Conn’s syndrome. The random cortisol level was notably elevated at 1334 nmol/L (reference range: 140 to 690 nmol/L).

Furthermore, a low-dose dexamethasone suppression test was undertaken due to the high cortisol levels. Following the administration of 1 mg of dexamethasone at 10 p.m., cortisol levels were measured at 9 p.m., 3 a.m., and 9 a.m. the following day. The results unveiled a persistently elevated cortisol level surpassing 1655 nmol/L, signaling an abnormal response to dexamethasone suppression and raising concerns about a hypercortisolism disorder, such as CS.

In the intricate progression of this case, the investigation delved deeper with a 24-hour urinary free cortisol level, revealing a significant elevation at 521 mcg/day (reference range: 10 to 55 mcg/day). Subsequent testing of ACTH portrayed a markedly elevated level of 445 ng/L, distinctly exceeding the normal reference range of 7.2 to 63.3 ng/L. A high-dose 8 mg dexamethasone test was performed to ascertain the source of excess ACTH production. The baseline serum cortisol levels before the high-dose dexamethasone suppression test were 1404 nmol/L, which decreased to 612 nmol/L afterward, strongly suggesting the source of excess ACTH production to be in the pituitary gland.

A CT scan of the adrenal glands ruled out adrenal mass, while an MRI of the brain uncovered a 1.3×1.3×3.2 cm pituitary macroadenoma (Figure 3), leading to compression of adjacent structures. Neurosurgery was consulted, and they recommended surgical removal of the macroadenoma due to the tumor size and potential complications. The patient was referred to a tertiary care hospital for pituitary adenoma removal.

Magnetic-resonance-imaging-(MRI)-of-the-brain-depicting-a-1.3x1.3x3.2-cm-pituitary-macroadenoma-(star)
Figure 3: Magnetic resonance imaging (MRI) of the brain depicting a 1.3×1.3×3.2 cm pituitary macroadenoma (star)

Discussion

CS represents a complex endocrine disorder characterized by excessive cortisol production. While the classic presentation of CS includes weight gain, central obesity, and muscle weakness, our case highlights an uncommon initial manifestation: severe hypokalemia. This atypical presentation underscores the diverse clinical spectrum of CS and the challenges it poses in diagnosis and management [1,2].

While CS typically presents with the classic symptoms mentioned above, severe hypokalemia as the initial manifestation is exceedingly rare. Hypokalemia in CS often results from excess cortisol-mediated activation of mineralocorticoid receptors, leading to increased urinary potassium excretion and renal potassium wasting. Additionally, metabolic alkalosis secondary to cortisol excess further exacerbates hypokalemia [3,4].

Diagnosing a case of Cushing’s disease typically commences with a thorough examination of the patient’s medical history and a comprehensive physical assessment aimed at identifying characteristic manifestations such as central obesity, facial rounding, proximal muscle weakness, and increased susceptibility to bruising. Essential to confirming the diagnosis are laboratory examinations, which involve measuring cortisol levels through various tests, including 24-hour urinary free cortisol testing, late-night salivary cortisol testing, and dexamethasone suppression tests. Furthermore, assessing plasma ACTH levels aids in distinguishing between pituitary-dependent and non-pituitary causes of CS. Integral to the diagnostic process are imaging modalities such as MRI of the pituitary gland, which facilitate the visualization of adenomas and the determination of their size and precise location [1-4].

Treatment for Cushing’s disease primarily entails surgical removal of the pituitary adenoma via transsphenoidal surgery, with the aim of excising the tumor and restoring normal pituitary function. In cases where surgical intervention is unsuitable or unsuccessful, pharmacological therapies employing medications such as cabergoline (a dopamine receptor agonist) or pasireotide (a somatostatin analogue) may be considered to suppress ACTH secretion and regulate cortisol levels. Additionally, radiation therapy, whether conventional or stereotactic radiosurgery, serves as a supplementary or alternative treatment approach to reduce tumor dimensions and mitigate ACTH production [5,6]. To assess the effectiveness of treatment, manage any problem, and assure long-term illness remission, diligent long-term follow-up and monitoring are essential. Collaborative multidisciplinary care involving specialists such as endocrinologists, neurosurgeons, and other healthcare professionals is pivotal in optimizing patient outcomes and enhancing overall quality of life [2,4].

The prognosis of CS largely depends on the underlying cause, stage of the disease, and efficacy of treatment. Early recognition and prompt intervention are essential for improving outcomes and minimizing long-term complications. Surgical resection of the adrenal or pituitary tumor can lead to remission of CS in the majority of cases. However, recurrence rates vary depending on factors such as tumor size, invasiveness, and completeness of resection [2,3]. Long-term follow-up with endocrinologists is crucial for monitoring disease recurrence, assessing hormonal function, and managing comorbidities associated with CS.

Conclusions

In conclusion, our case report highlights the rarity of severe hypokalemia as the initial presentation of CS. This unique presentation underscores the diverse clinical manifestations of CS and emphasizes the diagnostic challenges encountered in clinical practice. A multidisciplinary approach involving endocrinologists, neurosurgeons, and radiologists is essential for the timely diagnosis and management of CS. Early recognition, prompt intervention, and long-term follow-up are essential for optimizing outcomes and improving the quality of life for patients with this endocrine disorder.

References

  1. Nieman LK, Biller BM, Findling JW, Newell-Price J, Savage MO, Stewart PM, Montori VM: The diagnosis of Cushing’s syndrome: an Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2008, 93:1526-40. 10.1210/jc.2008-0125
  2. Newell-Price J, Bertagna X, Grossman AB, Nieman LK: Cushing’s syndrome. Lancet. 2006, 367:1605-17. 10.1016/S0140-6736(06)68699-6
  3. Torpy DJ, Mullen N, Ilias I, Nieman LK: Association of hypertension and hypokalemia with Cushing’s syndrome caused by ectopic ACTH secretion: a series of 58 cases. Ann N Y Acad Sci. 2002, 970:134-44. 10.1111/j.1749-6632.2002.tb04419.x
  4. Elias C, Oliveira D, Silva MM, Lourenço P: Cushing’s syndrome behind hypokalemia and severe infection: a case report. Cureus. 2022, 14:e32486. 10.7759/cureus.32486
  5. Fleseriu M, Petersenn S: Medical therapy for Cushing’s disease: adrenal steroidogenesis inhibitors and glucocorticoid receptor blockers. Pituitary. 2015, 18:245-52. 10.1007/s11102-014-0627-0
  6. Pivonello R, De Leo M, Cozzolino A, Colao A: The treatment of Cushing’s disease. Endocr Rev. 2015, 36:385-486. 10.1210/er.2013-1048

Filed under: Cushing's, symptoms | Tagged: , , , , , | Leave a comment »

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