A rare case of metastatic solitary fibrous tumor of the pancreas manifesting as a cystic neoplasm: a case report

Solitary fibrous tumor (SFT) is a rare mesenchymal tumor that typically arises from the pleura. Although it may appear in other organs, it rarely develops in the pancreas. We report herein a rare case of metastatic SFT of the pancreas originating from an intracranial tumor and subsequently identified as a cystic neoplasm of the pancreas. A 58-year-old woman with a past medical history of brain tumor visited the hospital for further investigation of a cystic tumor in the pancreas tail. Abdominal imaging showed a heterogeneously enhancing mass that was initially suspected as a neuroendocrine neoplasm, solid pseudopapillary neoplasm, or mucinous cystic neoplasm of the pancreas. Distal pancreatectomy was performed without any intraoperative and postoperative complications. Pathological findings confirmed a diagnosis of malignant SFT of the pancreas with hyperproliferative potential. A histopathological review of her brain tumor revealed that the pancreatic tumor was derived from her brain lesion. The patient developed recurrent brain disease 4 years after the pancreatectomy, but no recurrence has been observed in the abdominal cavity. SFT should be considered in the differential diagnosis of untypical hypervascular pancreatic mass, particularly in patients with a history of an intrathoracic or intracranial mesenchymal tumor. Immunohistochemical analysis is crucial in detecting this tumor entity. Hyperproliferative status indicates a malignant disease and requires careful postoperative observation.