A case of pancreatic oncocytic tumor

An uncommon case of potentially malignant oncocytoma arising in the pancreatic tail of 54-year-old woman is reported. The tumor was encapsulated and measured 11 x 7 x 6 cm. The tumor cells were uniform in appearance, plump and polyhedral, with distinct finely granular eosinophilic cytoplasm, and were arranged in solid acinar groups. Electron microscopy revealed that the tumor cells contained numerous mitochondria in the cytoplasm. In the present case, the tumor cells showed perineural and small venous invasion in the pancreas and potentially malignant characteristics. However, neither recurrence nor metastasis has been detected 3 years after resection. These findings indicate that the present tumor had apparent low-grade malignancy.