Idiopathic granulomatous hypophysitis mimicking adenoma.

Hypophysitis is a rare disease of pituitary gland, which, although it is usually a primary lesion, can also occur secondary to systemic conditions. Granulomatous hypophysitis is an inflammatory disease condition which accounts for less than 1% of all cellular lesions and can mimic adenoma. A 32-year-old woman presented with weight gain, galactorrhea and blurred vision. The MRI showed a cystic, nodular lesion in the intermediate lobe of the pituitary gland and the initial diagnosis was adenoma. She underwent surgery and the histopathology revealed granulomas composed of epithelioid histiocytes, multinuclear giant cells and mononuclear inflammatory cells. Inflammatory diseases of the pituitary gland are much less frequent than pituitary adenomas and idiopathic granulomatous hypophysitis is extremely rare. Histopathology and the ruling out of a systemic cause are the gold standards for its diagnosis.