Xanthomatous Hypophysitis Secondary to a Ruptured Rathke's Cleft Cyst: A Case Report.

Hypophysitis (HP) is a rare disease which develops secondary to chronic or acute inflammation of the pituitary gland and may cause symptoms related to pituitary dysfunction and mass compression. Lymphocytic HP is the most common subtype of primary HP, while xanthomatous HP (XHP) is considered the rarest form, with 35 reported cases, to date. A 35-year-old woman was initially admitted to a Gynecology clinic with a 2-year history of amenorrhea and headache. She was started on cabergoline 0.5 mg twice a week for macroprolactinoma. Due to persistent amenorrhea with low gonadotropins, she was referred to our Endocrinology clinic. Her pituitary function profile revealed panhypopituitarism and a 13×11×12 mm sized sellar mass with diffuse enhancement which sustained toward the infundibulum and dura was observed on the gadolinium-enhanced pituitary MRI. The patient underwent an endoscopic endonasal transsphenoidal approach for tumor resection and thick yellowish fluid draining from the lesion was observed. The histopathological diagnosis was reported as a rupture of an Rathke's cleft cyst and an XHP. The surgery did not improve the symptoms/pituitary functions, however, headache recovered immediately after the first dose of high dose methylprednisolone treatment. The inflammatory process in a xanthomatous lesion may actually be a secondary response to mucous fluid content release from a ruptured cyst, thus recommended to classify XHP as secondary hypophysitis. Since the differentiation of XHP from other pituitary tumors may be challenging preoperatively, surgery is the major diagnostic tool and also, the most recommended therapeutic option.