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.

Homogeneous and heterogeneous expression of prolactinomas, somatotropinomas, NS, and Cushing's disease can occur within families in the absence of MEN1/CNC. FIPA and sporadic cases have differing clinical characteristics. FIPA may represent a novel endocrine neoplasia classification that requires further genetic characterization.

The outcome of 24 months of cabergoline treatment on prolactin (PRL) normalization, tumor shrinkage, restoration of pituitary function, and semen alterations was prospectively investigated in 41 men with macro- (age 17-70 yr) and 10 with microprolactinoma (age 18-53 yr). Fifty-one age-matched men served as controls for semen analysis. At study entry, of the 41 patients with macroprolactinoma, 17 (41.4%) had visual field defects, 14 (34.1%) had headache, eight (19.5%) had galactorrhea, 22 (53.6%) had hypopituitarism apart from hypogonadism, and 30 (73.2%) had low testosterone levels; of the 10 patients with microprolactinoma, none had visual field defects, galactorrhea, or hypopituitarism apart from hypogonadism, two had headache (20%), and five had low testosterone levels (50%; P = 0.3). After 24 months of therapy, 1) PRL levels normalized in 31 patients with macro- (75.6%) and in eight with microprolactinoma (80%; P = 0.9), and galactorrhea disappeared in all patients; 2) maximal tumor diameter reduced by 73.7 +/- 22.6% in macro- and 72.8 +/- 28.3% in microprolactinomas (P = 0.91), and 15 macro- (30%) and seven microprolactinomas (46.7%; P = 0.37) disappeared; 3) visual field defects disappeared in 15 (75%) patients with macroprolactinoma, and headache disappeared in 15 (83%) patients with macro- and in one with microprolactinoma (50%); 4) GH secretion recovered in 62.5% and ACTH secretion in 60% of patients; 5) testosterone levels normalized in 25 patients with macro- (60.9%) and six with microprolactinoma (60%) after 6 months, and 20 patients required testosterone or gonadotropin replacement (in 14 or six patients, respectively); and 6) sperm volume and count normalized in all patients who normalized testosterone levels, whereas motility normalized in more than 80%. Cabergoline therapy was well tolerated; only 4.5% of patients had side effects at high doses. These data demonstrate that cabergoline treatment is as effective and safe in men as in women with prolactinoma and can be successfully used as primary therapy even in men bearing large macroprolactinomas.

No abstract