Acromegaly and hyperprolactinemia in McCune-Albright syndrome. Evidence of hypothalamic dysfunction.

In a 21-year-old woman with McCune-Albright syndrome, acromegaly and hyperprolactinemia with hypopituitarism developed secondary to a large pituitary tumor. Bromocriptine suppressed the secretion of growth hormone and prolactin, with a reduction in tumor size. However, at the age of 8, she already showed evidence of biochemical acromegaly, with a paradoxical rise of growth hormone levels during two glucose tolerance tests, in the presence of a radiologically normal pituitary fossa. These data support the hypothesis that long-standing hypothalamic stimulation may have been responsible for the later development of a pituitary tumor.