RESUMEN
A 59-year-old male patient was transnasally operated on because of a pituitary adenoma with hypopituitarism. A second operation and X-ray therapy followed a half year later due to recurrent tumor. Both neoplasmas were classified as sparsely granulated prolactin cell adenomas. Immunohistochemical studies revealed strong immunoreactivity for prolactin and FSH in the tumor cells of both the pituitary adenoma and the recurrent tumor. Two years later the prolactin plasma levels were extremely elevated. A tumor in the liver was identified. Biopsy revealed a solid endocrine tumor containing prolactin by immunohistology. Due to structural and immunohistological similarities this tumor could be identified as a metastasis of the pituitary tumor. After 5 months of therapy the patient died from thrombembolism. Post-mortem studies confirmed the diagnosis of a metastasizing prolactin-secreting pituitary carcinoma. Only six similar cases have been reported in the literature. Our case report confirms the experience with 35 definite pituitary carcinomas reparted in the current literature: malignant pituitary tumors develop after pituitary surgery and can be identified not from the pituitary tumor, but only from its metastases.