Prolactinomas are adenomas of the anterior lobe of the pituitary gland that produce prolactin. They are the most common type of pituitary gland adenomas, and they are associated with hyperprolactinemia. The majority of prolactinomas occur in women (>70%) with a minority of cases reported in children.

In premenopausal women, oligomenorrhea, amenorrhea, infertility, and, less often, spontaneous or expressive galactorrhea may be seen. Vaginal dryness and dyspareunia may also be features. Signs include decreased bone mineral density.

In postmenopausal women, presenting symptoms are related to the space-occupying effects of the tumor (headaches, visual disturbances such as bitemporal hemianopsia, etc) because they are already hypoestrogenic.

In men, symptoms may include impotence, infertility, decreased libido, and, rarely, gynecomastia.

Prolactinomas are nonmalignant lesions. They warrant treatment if they grow to a size resulting in neurologic symptoms or if resultant prolactinemia causes distressing symptoms or infertility.