Male gonadotroph adenoma: report of three cases and a review of the literature.

We herein report three cases of gonadotroph adenoma in men (36-72 years of age) presenting with visual impairment and suprasellar masses measuring approximately 20 to 30 mm in diameter. Endocrinological examinations were normal, except for slightly increased follicle stimulating hormone (FSH) levels in two cases. Based on the tentative diagnosis of non-functioning pituitary adenoma, transsphenoidal surgery was performed, which revealed that the tumors consisted of FSH- and LH-positive cells. As gonadotroph adenoma is very common among patients with clinically silent pituitary adenoma, it should be diagnosed using pathological examinations.