A case of pancreatic schwannoma - The features in imaging studies compared with its pathological findings: Report of a case.

Pancreatic schwannoma is a very rare tumor that tends to be confused with other pancreatic tumors preoperatively. We report a case of schwannoma of the pancreatic head. A 40-year-old woman was admitted to our hospital for treatment of a pancreatic tumor which was found by medical checkup. It was a well-defined solid tumor exhibiting heterogeneous enhancement with some necrotic foci on contrast-enhanced computed tomography (CT) and on magnetic resonance imaging (MRI). Angiography and CT during arteriography revealed the main feeding arteries of the tumor to be the posterior and anterior superior pancreaticoduodenal arteries. Fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) showed accumulation of FDG in the tumor with a maximum standardized uptake value of 3.6. We diagnosed a solid pseudopapillary neoplasm or a pancreatic neuroendocrine tumor preoperatively and performed pylorus-preserving pancreaticoduodenectomy. The tumor had well a well-defined capsule and was composed of a large solid portion containing spindle cells and a smaller hemorrhagic portion containing hypocellular stroma, and diagnosed as pancreatic schwannoma by immunohistochemistry. In this case, CT during arteriography was useful in determining the origin of the tumor. MRI reflected the pathological features of the tumor. The most important finding was that FDG-PET showed abnormal accumulation of FDG in the benign pancreatic schwannoma.