Cushing's disease and hyperprolactinemia due to a mixed ACTH- and prolactin-secreting pituitary macroadenoma.

A 36-year-old man with depression, Cushingoid features and hypogonadism was found to have simultaneous pituitary-dependent Cushing's disease and marked elevation of serum prolactin (PRL). CT-scan revealed a macroadenoma with suprasellar extension. Transphenoidal surgery cured the patient's Cushing's disease, but failed to correct his hyperprolactinemia, which was controlled by subsequent bromocriptine therapy. Immunostaining of the pituitary tumor was positive for PRL as well as for ACTH, and ACTH-related peptides beta-lipotropin and beta-endorphin in two distinct tumor cell lines. This pituitary tumor is one of the few mixed PRL- and ACTH-secreting tumors documented by immunostaining. It is the second reported in a macroadenoma, in which PRL-secreting tumoral cells are much more abundant than ACTH-secreting cells.