A very rare, malignant, epithelial tumor of the pancreas characterized, macroscopically, by a usually large, well-circumscribed, fully or partially encapsulated, solid mass, often with hemorrhage, necrosis and cystic changes, in any portion of the pancreas and, histologically, by neoplastic cells with variable degrees of differentiation and morphology, ranging from acinar structures similar to normal pancreatic acini to large sheets of poorly differentiated neoplastic cells. Presenting symptoms are typically non-specific and include abdominal pain, weight loss, vomiting, nausea, and/or, less commonly, jaundice. Immunohistochemical evidence of acinar-specific products is observed. Association with Lynch syndrome, familial adenomatous polyposis, and pancreatic panniculitis has been reported.

A malignant tumor arising from epithelial cells. Carcinomas that arise from glandular epithelium are called adenocarcinomas, those that arise from squamous epithelium are called squamous cell carcinomas, and those that arise from transitional epithelium are called transitional cell carcinomas (NCI Thesaurus).