Oncocytic type intraductal papillary mucinous neoplasm mimicking mucinous cystic neoplasm of the pancreas - A case report -

Oncocytic type intraductal papillary mucinous neoplasm is a newly defined subgroup of intraductal papillary mucinous neoplasms. A 35-year-old woman presented complaining of epigastric pain for one month. Enhanced computed tomography revealed a multilocular cystic mass in the distal body and tail of the pancreas. Endoscopic retrograde cholangiopancreatography showed no communication between the mass and the main pancreatic duct. The patient underwent a distal pancreatectomy and splenectomy. Microscopical examination showed a fibrous cyst wall; polypoid tumors exhibiting thin stalks, with extensive arborizing papillary growths from these stalks; and a focally cribriform pattern, lined by plump cells with abundant eosinophilic and granular cytoplasm. Red granules were detected in the cytoplasm of tumor cells on modified Gomori trichrome stain. Ultrastructurally, the tumor cells contained abundant cytoplasm packed with numerous mitochondria and intracellular and intercellular lumina. We describe an oncocytic type intraductal papillary mucinous neoplasm having the clinical characteristics of a mucinous cystic neoplasm.