Rare hypervascular pancreatic tumors diagnosed as asynchronous metastases of central nervous system solitary fibrous tumor/hemangiopericytoma.

A 70-year-old woman was referred to our hospital for asymptomatic pancreatic tumors. She had a history of hemagiopericytoma (HPC) about 20 years ago, and no apparent recurrence has been observed. Contrast-enhanced computed tomography revealed two hypervascular tumors in the head and uncinate process of the pancreas, and no obvious neoplastic lesions were found in other organs. Endoscopic ultrasound guided fine-needle aspiration cytology was performed and histopathology showed that spindle-shaped tumor cells were arranged in a hemangiopericytoma-like pattern and positive for STAT6, which was a characteristic feature of solitary fibrous tumors (SFTs). Immunohistochemical staining for surgical pathology specimens from past HPC showed positive expression of STAT6, which was Grade 2 central nervous system solitary fibrous tumor/hemagiopericytoma (CNS SFT/HPC) according to the current WHO classification. From these findings, the pancreatic tumors were preoperatively diagnosed as pancreatic metastases of CNS SFT/HPC. She underwent pancreaticoduodenectomy. Histopathological examination of the surgically resected specimen proved that the both pancreatic tumors were SFT/HPC. Thus, pancreatic tumors were finally diagnosed as asynchronous pancreatic metastases from CNS SFT/HPC. Although extremely rare, metastatic pancreatic tumors derived from SFT/HPC should be considered as a differential diagnosis for hypervascular pancreatic tumors, especially when having a past history of brain tumors.