Mucinous cystic neoplasm of the pancreas with high carcinoembryonic antigen.

A large mucinous cystic neoplasm of the pancreas was found that showed a remarkably high carcinoembryonic antigen (CEA) level in cyst content. Staining for CEA was also detected in the lining epithelium. These findings indicate that columnar epithelial cells secrete CEA that accumulates in the cyst. We suggest that a CEA level determination of the cyst fluid, along with CEA immunoperoxidase staining on cell preparations, may prove useful in providing an accurate diagnosis of pancreatic cystic tumors.