A case of malignant cystic endocrine tumor of the pancreas.

A malignant pancreatic endocrine tumor with a cystic appearance in a 66-yr-old woman was reported. Total pancreatectomy was performed under the diagnosis of cystadenocarcinoma. The tumor was large and cystic, but the solid portion of the tumor showed histologically a ribbon-like array of small uniform cells typical for endocrine tumors. Immunohistochemically, most tumor cells were immunoreactive for neuron-specific enolase, chromogranin, and Leu 7-epitope. Ultrastructurally, innumerable neurosecretory granules were demonstrated in the cytoplasm of most tumor cells. The patient survived for 5.5 yr after operation despite liver metastases, some of which also showed cystic appearances.