Primary Pure Pancreatic -Type Acinar Cell Carcinoma of the Stomach: A Rare Entity with a Difficult Diagnosis and Review of the Literature.

Acinar cell carcinoma is an uncommon tumour, representing only 1% to 2% of all exocrine pancreatic tumours. Pancreatic-type acinar cell carcinoma can occur in other organs, including the stomach, but it is extraordinarily rare. We report a case of a 51-year-old woman with a pancreatic-type pure acinar carcinoma of the stomach coexisting with a large cell B lymphoma synchronously, and a literature review of gastric carcinomas with pancreatic cell differentiation. At present there is a preoperative underdiagnosis of these tumours that could be minimized by including this entity in the differential diagnosis of gastric cancer and by performing immunohistochemical analysis with neuroendocrine markers and exocrine pancreatic enzymes.