Ectopic Functional Adenoma in the Cavernous Sinus: A Diagnostic and Surgical Challenge

Object: Ectopic pituitary adenomas are extremely rare and mostly arise in the proximity of the pituitary gland, e.g., the cavernous sinus (CS), the pituitary stalk or the suprasellar space. Their location may be a common cause of failed diagnosis and unsuccessful transsphenoidal surgery. We present a case of mixed ACTH- and PRL-secreting adenoma located in the left CS.

Methods: A 36 year old female presented with amenorrhea for over a year and cushinoid features. Increased PRL, ACTH and cortisol levels were identified however the pituitary MRI failed to reveal a pituitary tumor; instead, a parasellar lesion in the left CS was noticed. Inferior petrosal sinus sampling (IPSS) demonstrated a significant central-to-peripheral and lateralized left-sided ACTH gradient. The patient underwent endoscopic endonasal surgery (EES). No tumor was found on sellar exploration, however, the left CS was widely explored and a tumor was found lateral to the paraclival segment of the carotid artery (video). There were no complications following EES. Pathology confirmed the diagnosis of a mixed ACTH- and PRL-secreting adenoma. During the immediately postoperative course, PRL levels returned to normal and ACTH levels dropped below 5 μg/dl. Postoperative MRI demonstrated complete tumor resection. At 3 months follow-up, the patient is in clinical and biochemical remission of Cushing’s Disease and she has initiated menstruation following progesterone challenge test.

Conclusion: Complete surgical resection of functional pituitary adenomas is the gold standard of treatment. Ectopic location of these tumors may compromise both the early diagnosis and the surgical success. EES is the ideal approach for ectopic intracavernous adenomas allowing for a wide exploration of the CS and complete resection of the tumor with no surgical complications.