Abscess-like formation concomitant with pituitary adenoma in Cushing's disease: case report and pathological considerations.

Pituitary abscess is a rare condition and a histological misnomer since cultures of abscess material are often negative or non-pathogenic. We report the first case of pituitary abscess-like formation concomitant with pituitary adenoma and discuss the physiopathological mechanism. A 37-year-old woman presented classic symptoms of Cushing's disease. Endocrine studies indicated the presence of adenocorticotropin (ACTH)-producing pituitary adenoma. Preoperative magnetic resonance imaging revealed two separate tumours of the pituitary. During transsphenoidal surgery, a 14-mm adenoma was removed from the right side of the gland and a pus-filled cystic tumour was opened and drained on the left. Histological diagnosis was ACTH-producing pituitary adenoma and cyst material compatible with pituitary abscess. Association of separate adenoma and abscess of the pituitary gland has not been reported previously. We speculate that spontaneous adenoma infarction may provide a more comprehensible pathophysiological explanation than abscess formation.