MON-251 Xanthogranulomatous Hypophysitis: A Rare Case of Hypopoituitarism

The patient is a 54-year-old male with type 2 diabetic treated with insulin who presented with a two-week history of fever nausea and vomiting. He subsequently developed seizure episodes with changes in mental status prompting a visit to the emergency room. Upon admission the patient was hypotensive and lethargic. After an initial improvement, he developed polyuria (14-15 liters per day) in the context of eunatremia and specific gravity of 1010. His initial evaluation revealed a serum a.m. cortisol of 1.2 mcg/dL (6.2 to 19.4), low free T4 of 0.64 Ng/dl) 0.9-1.7) and secondary hypogonadism with a total testosterone of less than 2.5 ng/dL (181-772). Hormonal replacement was initiated. MRI of the brain revealed heterogeneous sellar lesion measuring 2.1 x 2.0 x 2.0 cm with peripheral enhancement following contrast administration and deviation of the pituitary stalk to the right. The lesion invaded the left cavernous sinus (Knosp III) and abutted the optic chiasm. He underwent an uneventful transsphenoidal tumorectomy revealing extensive coagulation necrosis with chronic lymphocytic infiltration, numerous macrophages and multinucleated giant cells with deposits of hemosiderin, cellular debris and isolated cholesterol crystals surrounded by granulomatous tissue. The pathology was compatible with xanthogranulomatous hypophysitis. We report a rare case of Xanthogranulomatous hypophysitis (XGH), the least common subtype of pituitary hypophysitis often mistaken by a neoplastic lesion. It is more common in young adults occurring in isolation, as a secondary reaction to a local process such as apoplexy part or as part of a systemic condition with autoimmune aetiology, often resulting in variable degrees of anterior and posterior pituitary deficiencies.