Cystic schwannoma of the pancreas.

Intrapancreatic schwannoma is a rare neoplasm. We report a case of a 46-year-old man with a cystic schwannoma in the head of the pancreas. This tumor, based on clinical manifestations and radiologic features, was initially suspected to be a cystic mucinous tumor of the pancreas or a pseudocyst. Histologically, the tumor was a typical schwannoma with cyst formation caused by degenerative changes. Immunostaining showed the tumor cells to be strongly and diffusely positive for S-100 protein, vimentin, and CD56, and negative for cytokeratin AE1/AE3, desmin, smooth muscle myosin specific, CD34, and CD117, which support the diagnosis of schwannoma. Cystic schwannoma is a rare neoplasm occurring in the pancreas and should be considered in the differential diagnoses for patients presenting with pancreatic cystic lesions.