Malignant prolactinoma: is metastasis a must? Clinico-pathologic and immunohistochemical study of a case

Pituitary carcinomas are rare tumors which have been conventionally defined as primary adenohypophyseal tumors with cerebrospinal or extracranial metastases. According to the current criteria even a highly invasive tumor without metastases is not considered as malignant. A case of pituitary adenoma is reported with an unproven site of metastasis but with rapid increase in prolactin levels (35,000 ng/ml), showing extensive invasion on radiology, and pathological and immunohistochemical studies indicating a highly mitotic variety of tumor. On the basis of this case we want to emphasize that extracranial metastasis is not a must to label a pituitary adenoma as a malignant tumor. Such aggressive behavior of the tumor and clinico-pathological course in itself should be sufficient for the tumor to be labeled as malignant.