[Macroprolactinoma resistant to bromocriptine]

A 24 year old female with amenorrhea-galactorrhea due to a pituitary macroprolactinoma that eventually responded to bromocriptine with improvement of visual fields and intracranial hypertension syndrome is presented. After 2 years of treatment with bromocriptine her symptoms relapsed and she underwent transphenoidal hypophysectomy. The high serum prolactin levels detected initially decreased under bromocriptine to ward normal levels and was not modified after surgery, while gonadotropin production remain scarce. Growth hormone (GH) serum levels despite its normal concentration decreased significantly (p = less than 0.5) after pituitary ablation. We assume that the lack of response to bromocriptine in this case could have been due to a mixed hormonal nature of the tumor without overproduction or clinical expression of GH activity.