The epidemiology of prolactinomas.

Prolactin-secreting tumors (prolactinomas), the most frequently occurring pituitary tumor, have a frequency that varies with age and sex. They occur most frequently in females aged 20 to 50 years old, at which time the female-to-male ratio is approximately 10:1. In the pediatric-adolescent age group, prolactinomas have a prevalence of 100/million population, and account for less than 2% of all intracranial tumors. Prolactinomas occur in approximately 30% of patients with multiple endocrine neoplasia type 1 and in this setting, they may be more aggressive than their sporadic counterparts. Patients with Carney complex or McCune-Albright syndrome may exhibit hyperprolactinemia due to a pituitary tumor derived from somatomammotropic cells that secrete both growth hormone and prolactin. Few familial cases of prolactinoma unrelated to MEN-1 are reported in literature.