Herein, we report the case of a 28-year old woman clinically presenting with unclear
weight gain over the last years. The patient displayed facial and neck
edema in combination with unobtrusive
striae distensae. Endocrinological examinations led to the diagnosis of
Cushing's disease. Neuroradiological examination revealed an intrasellar
tumor mass of 7 mm in diameter. Subsequently, transsphenoidal
tumor resection was performed. Histological and immunohistochemical investigations revealed a pituitary gland
adenoma showing a biphasic
tumor growth pattern with two morphologically different
tumor areas producing
ACTH and
prolactin respectively. Co-expression of
ACTH and
prolactin is exceedingly rare in
pituitary adenoma. To our surprise, both
tumor areas exhibited features of atypia consisting in elevated MIB-1 proliferation index in the
ACTH-producing portion as well as p53 expression selectively in the
prolactin-producing
tumor parts. To our knowledge, this is the first case of an
ACTH- and
prolactin-producing pituitary gland
adenoma exhibiting biphasic features of atypia.