Portal vein leiomyosarcoma invading the pancreatic head.

We encountered a rare case of a pancreatic head tumor protruding into the portal vein, later diagnosed histopathologically as primary leiomyosarcoma of the portal vein. A 59-year-old woman visited our hospital because of an elevated amylase level during a medical checkup. Computed tomography showed a moderately contrasted, well-defined mass of 35-mm diameter in the pancreatic head with protrusion into the portal vein. Endoscopic ultrasonography revealed a well-defined and hypoechoic mass. Fluorodeoxyglucose-positron emission tomography showed a high accumulation of fluorodeoxyglucose in the pancreas head. We performed a subtotal stomach-preserving pancreaticoduodenectomy with portal vein resection. Gross findings of the fixed specimen showed a white solid, multinodular mass in the pancreatic parenchyma with protrusion into the portal vein. Histopathological examination showed proliferation of spindle-shaped eosinophilic cells with intricate bundle-like growth, indicating leiomyosarcoma. Examining the tumor location and invasion suggested portal vein as the origin. Although portal vein primary leiomyosarcoma is rare, leiomyosarcoma should be considered as a differential diagnosis in pancreatic head tumors with protrusion into the portal vein. Precise macroscopic and histopathological examinations can help determine the definitive diagnosis and origin of leiomyosarcoma.