Prolactin cell carcinoma of the pituitary.

Two patients with malignant prolactinoma are reported. The diagnosis of malignancy depends on the demonstration of invasion of brainstem and subarachnoid space and on the presence of marked cellular pleomorphism and mitotic activity. Review of the literature revealed that such malignant tumors were more common in men than in women. The most frequency intracranial sites of metastases were frontal and occipital lobes, and cerebellum. The possibility of radiation-induced carcinomatous transformation is discussed.