Intraductal acinar cell carcinoma of the pancreas

We describe a purely intraductal acinar cell carcinoma involving branch duc ts of the pancreas in a 74-year-old man, which presented as recurrent episo des of acute pancreatitis. Endoscopic ultrasound examination revealed an in traductal mass bulging into the main pancreatic duct suggesting, pre-operat ively, an intraductal mucinous papillary tumour. Gross examination showed s everal dilated branch ducts that contained haemorrhagic tumour material wit hout any solid or true cystic formation within the pancreatic parenchyma. U sing histology, a purely intraductal acinar cell carcinoma was observed, in volving branch ducts only, associated with foci of carcinoma in situ in adj acent exocrine parenchyma. The main pancreatic duct was free of disease exc ept for its communication with a cancerous branch duct. A concomitant neuro endocrine microadenoma was incidentally found during slide screening. Immun ohistochemistry performed on the intraductal proliferation confirmed zymoge n secretion with positive staining for alpha-1 anti-chymotrypsin and anti-t rypsin and the persistence of diastase-periodic acid-Schiff positive granul es in the apical pole of the tumour cells. Neuroendocrine markers were nega tive in the acinar cell carcinoma and positive in the neuroendocrine microa denoma. To our knowledge, this is the first report of an intraductal acinar cell carcinoma of the pancreas involving branch ducts and sparing the main pancreatic duct.