[Hypophyseal microprolactinoma as a cause of delayed puberty].

Hyperprolactinaemic hypogonadism in adults is a well defined disease with clinical symptoms like ovarian hypofunction or amenorrhea and galactorrhea in females and loss of sexual activity in males. In pediatrics this special form of hypogonadism is almost unknown. Typical manifestation is delay in puberty or pubertal arrest. We describe a 20 year old man with signs of delay of puberty. Endocrinological work-up revealed a decreased pulse frequency of luteinizing hormone resulting in pathologically low testosterone concentrations. The final cause of hypothalamic hypogonadism was a prolactin producing pituitary microadenoma. During long-term treatment with a dopaminergic drug the elevated prolactin levels decreased to the normal range and testicular function normalized as shown by growth of the testes and increasing testosterone levels.