Acinar cell carcinoma of the pancreas.

A case of acinar cell carcinoma of the pancreas is presented. The differential diagnosis is discussed and includes endocrine neoplasm of the pancreas (islet cell and carcinoid tumor) and a poorly differentiated adenocarcinoma. The separation of the various entities by light microscopic, histochemical, immunocytochemical, and ultrastructural methods is described. The acinar cell carcinoma characteristically is positive for pancreatic digestive enzymes by immunocytochemistry, and at the ultrastructural level zymogen-type granules can be demonstrated; these have a tendency to aggregate in the apical region of acinar structures. Clinically the acinar cell carcinoma is an aggressive malignant neoplasm that may present with a characteristic syndrome of disseminated fat necrosis. Survival is generally less than 1 year.