Carcinosarcoma of the pancreas arising in a mucinous cystic neoplasm.

We report a carcinosarcoma of the pancreas in a 67-year-old woman who presented with nausea, vomiting, and painless jaundice. A work-up demonstrated a well-circumscribed mass in the head of the pancreas. After pylorus-preserving pancreaticoduodenectomy, the tumor was found to be grossly yellow, and it compressed the common bile duct and pancreatic duct. Histological examination of the neoplasm showed a 4.0 x 4.0 x 3.0-cm mucinous cystadenocarcinoma with invasive poorly differentiated carcinoma, well-differentiated squamous cell carcinoma, and sarcomatous stroma invading into the duodenum. There was no evidence of nodal metastasis (pT3N0M0). Immunohistochemical studies showed that the epithelial cells stained positive for cytokeratin 7, cytokeratin AE1/3, cytokeratin monoclonal antibody 5.2, epithelial membrane antigen, M-carcinoembryonic antigen, and low-molecular-weight kininogen, and the sarcomatous component was immunoreactive with vimentin. The patient had an uneventful recovery, but died 4 months later of rapidly progressive metastatic disease to the liver and peritoneum. To the best of our knowledge, this is the second case of carcinosarcoma with invasive epithelial and sarcomatous areas in the background of a mucinous cystic neoplasm of the pancreas.