Utility of Intraoperative Ultrasound in Identifying Pituitary Adenoma Hidden Behind a Cystic Lesion in Cushing’s Disease

Posted on May 29, 2025 by MaryO

Highlights

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    Intraoperative ultrasound enhances tumor localization during endoscopic pituitary surgery for MRI-negative Cushing’s disease.
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    Our findings support intraoperative US as a valuable adjunct in cases where preoperative imaging fails to reveal a lesion.
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    Further studies are expected to validate the efficacy of intraoperative ultrasound as a useful tool for MRI-negative Cushing’s disease.

Abstract

Cushing’s disease with inconclusive MRI findings presents a significant diagnostic and surgical challenge due to the difficulty in localizing the causative pituitary adenoma. This case report highlights the use of intraoperative ultrasound as an adjunct for tumor detection and successful resection in a Cushing disease patient with hidden adenoma. A 55-year-old female with a history of hypertension, diabetes, and a recent cerebral infarction presented with clinical and biochemical features of Cushing’s disease. Brain MRI revealed a 10 mm non-enhancing cystic lesion in the sella, making it difficult to confirm the underlying pathology. Inferior petrosal sinus sampling suggested a right-sided lesion, leading to an endoscopic endonasal transsphenoidal surgery. Intraoperatively, ultrasound was employed to assess the sellar region, initially identifying a cystic structure consistent with a Rathke’s cleft cyst. Following fluid drainage, ultrasound revealed an iso-echoic lesion with a distinct margin, which was subsequently resected and confirmed as a pituitary adenoma on histopathological examination.
The patient experienced postoperative biochemical remission, with normalization of ACTH levels and resolution of hypertension and diabetes. This case demonstrates that intraoperative ultrasound can be a valuable tool for tumor localization in suspicious MRI-negative Cushing’s disease. By aiding in the identification of adenomas obscured by cystic lesions or surrounding structures, intraoperative ultrasound may improve surgical outcomes. Further studies are warranted to validate its efficacy in routine clinical practice.

Introduction

Cushing’s disease is caused by an adrenocorticotropic hormone (ACTH)-secreting pituitary adenoma, leading to hypercortisolism and significant metabolic disturbances. Magnetic resonance imaging (MRI) is the primary imaging modality for detecting pituitary adenomas; however, in approximately 30–40 % of cases, no visible adenoma is detected, a condition known as MRI-negative Cushing’s disease [1,2]. The absence of a discernible lesion on MRI poses a diagnostic and therapeutic challenge, often necessitating additional testing such as bilateral inferior petrosal sinus sampling (IPSS) to confirm pituitary-dependent Cushing’s syndrome [3]. Given the limitations of imaging, treatment strategies for MRI-negative Cushing’s disease require a multimodal approach.
The first-line treatment for Cushing’s disease, regardless of MRI findings, is transsphenoidal surgery. However, MRI-negative cases are associated with lower remission rates due to the difficulty in localizing the microadenoma intraoperatively [4]. When surgery fails or is not feasible, alternative treatments such as repeat surgery, radiotherapy, bilateral adrenalectomy, or medical therapy are considered [5]. Despite these therapeutic options, long-term disease control remains challenging, highlighting the need for improved diagnostic tools and targeted treatment strategies.
The authors aim to report the use of intraoperative ultrasound in a Cushing disease patient with hidden adenoma, demonstrating its possibility to detect tumors that were not visible on MRI and facilitate successful tumor resection, ultimately leading to remission.

Section snippets

Case report

A 55-year-old female patient was referred from the endocrinology department for evaluation of Cushing’s disease. She had been on medication for hypertension and diabetes for the past seven years. Two months prior, she suffered an acute cerebral infarction, resulting in left-sided hemiparesis.
The endocrinology department diagnosed her with Cushing’s disease based on a dexamethasone suppression test. Brain MRI revealed a 10 mm non-enhancing cystic mass in the right side of the sella. (Fig. 1) Due…

Diagnostic approach for MRI-negative cushing’s disease

Diagnosing MRI-negative Cushing’s disease is particularly challenging due to the absence of a visible pituitary adenoma on standard imaging. A stepwise diagnostic approach is necessary to confirm the presence of ACTH-dependent hypercortisolism, differentiate between pituitary and ectopic sources, and localize the tumor. The initial step involves biochemical confirmation of endogenous hypercortisolism through tests such as the 24-hour urinary free cortisol, and the low-dose dexamethasone…

Conclusion

MRI-negative Cushing’s disease presents significant challenges not only for neurosurgeons but also for endocrinologists. The conventional hypophysectomy is invasive and has a high risk of causing other complications. The present case report showed that intraoperative ultrasound can be used effectively in a Cushing disease patient with hidden adenoma. We hope to derive more definitive conclusions through future case studies.

CRediT authorship contribution statement

Min Ho Lee: Writing – review & editing, Writing – original draft, Data curation, Conceptualization. Tae-Kyu Lee: Writing – review & editing, Conceptualization.

Ethics approval

The study was approved by the appropriate institutional research ethics committee and certify that the study was performed in accordance with the ethical standards as laid down in the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards.
Informed consent was obtained from the patient included in this study.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

References (28)

More at https://www.sciencedirect.com/science/article/abs/pii/S0967586825002516

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