Ectopic Presentation of a Corticotroph Pituitary Adenoma in the Cavernous Sinus Mimicking a Radiographic Cavernous Hemangioma

Background: Because of the proximity to critical neurovasculatures, resection of aggressive pituitary adenomas invading the medial wall of the cavernous sinus is traditionally discouraged. However, when functional pituitary adenomas present ectopically in the cavernous sinus, a thorough workup is necessary to distinguish between the broad differential of lesions that can present in that area, followed by careful evaluation of the surgical indications and approach to treatment. Here, we report the case of a patient referred to radiation for a presumed radiographic cavernous hemangioma, later identified as an ectopic functional corticotroph adenoma in the cavernous sinus.

Report of a Case: 68-year-old female presented with headaches and diplopia. Magnetic resonance imaging (MRI. revealed a non-enhancing, 1 cm T2 hyperintense cavernous sinus lesion radiographically presumed to be a cavernous hemangioma. She was evaluated by a neurosurgeon and referred to radiation oncology for radiosurgery out of concern for surgical morbidity with resection of a cavernous hemangioma. After consultation, she was presented at multidisciplinary tumor board where further endocrine workup was recommended. This revealed elevated adrenocorticotropic hormone (ACTH), elevated midnight salivary cortisol, and elevated glycated hemoglobin, and an abnormal dexamethasone suppression test raising suspicion for central Cushing’s Disease. Inferior petrosal sinus sampling (IPSS. was consistent with central Cushing’s Disease and suggestive of a corticotroph adenoma on the left side. The patient underwent endoscopic endonasal resection with exploration of the left cavernous sinus and resection of the medial wall. Her cortisol fell to a nadir of <2 mcg/dL, consistent with biochemical remission. She was discharged on postoperative day (POD. 4 on physiological adrenal hormone replacement and followed up most recently at 3 months with no recurrence of symptoms.

Discussion: We present a case where a cavernous sinus lesion, initially presumed to be a cavernous hemangioma, was determined to be a corticotroph adenoma after neuroendocrine testing and it was resected with biochemical remission. Distinguishing these entities with MRI is challenging as they share similar imaging features; cavernous hemangiomas are typically hyperintense T2-weighted with homogenous contrast-enhancement, and while pituitary adenomas are heterogenous, they can appear very similarly.^1-3 Furthermore, due to the complex sellar-cavernous anatomy, MRI is insufficient to definitively determine involvement of the cavernous sinus.⁴ The Knosp scoring system does correlate with invasion, as many as 30% of Knosp grade 3 tumors do not invade the cavernous sinus intraoperatively.⁵ Although resection of the medial cavernous sinus wall is controversial, recent work from multiple groups has demonstrated its safety and utility in biochemical remission of functional tumors.⁶

Conclusion: Diagnosis and treatment of cavernous sinus lesions presents a unique challenge due to delicate surrounding neurovasculature and broad differential diagnosis. Surgical resection by endonasal endoscopic transsphenoidal approach can allow for safe and effective treatment of such lesions. This report highlights the utility of both comprehensive endocrine evaluation and precise imaging for patients with cavernous sinus lesions and recognizes the importance of medial wall resection in achieving complete resection of ectopic or invasive functional pituitary adenomas.

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Artikel online veröffentlicht:
05. Februar 2024