Acinar cell carcinoma: A possible diagnosis in patients without intrapancreatic tumour

BackgroundAcinar cell carcinomas of the pancreas are rare neoplasms. Usually diagnosed at an advanced stage, in general they are large solid pancreatic tumours with an average size of more than 10 cm.Aims and resultsWe report 3 cases of acinar cell carcinomas involving the peripancreatic lymph nodes, the liver hilum and the colon respectively, without clinical or pathological evidence of pancreatic tumours. These highly cellular neoplasms showed a predominantly acinar cell differentiation intermingled with a ductal component, with intracellular or extracellular mucin production by at least 25% of tumour cells. In addition, one case showed endocrine differentiation. Diffuse immunoreactivity for acinar enzymes trypsin and chymotrypsin was present in all cases.ConclusionThe occurrence of acinar cell carcinomas outside the pancreas underlines the notion that acinar cell carcinomas may originate in extrapancreatic sites and probably develop from heterotopic or metaplastic pancreatic foci present along the biliary tract.