Definition of Prolactinoma - males:

Prolactinomas are benign tumors of the pituitary gland that secrete prolactin. This hormone is best known for inducing milk production in women, but it also serves as a regulator of sexual function in men.

Causes, incidence, and risk factors:

Prolactinomas are the most common pituitary tumors. Men and women are equally likely to be affected. However, smaller tumors (microadenomas) are more common in women, probably because of earlier detection.

Prolactinomas may occur alone or as part of multiple endocrine tumor syndromes.