BACKGROUND: Extrahepatic portal vein aneurysm is a rare clinical entity with no more than 50 reported cases in the English literature. This study was to elucidate the procedures used in the diagnosis and management of portal vein aneurysm. METHOD: The clinical data of a patient with extrahepatic portal vein aneurysm were analyzed. RESULTS: Extrahepatic portal vein aneurysm associated with portal hypertension and splenomegaly was diagnosed by color Doppler ultrasonography (US), computed tomography (CT), magnetic resonance angiography (MRA) and angiography (indirect portography). Splenectomy and surgical shunt (splenorenal shunt) were performed. No hepatic encephalopathy and variceal bleeding occurred after the operation except mild pancreatic leakage caused by partial pancreatic tail resection. The patient recovered well. CONCLUSIONS: Extrahepatic portal vein aneurysm can be evaluated by US, CT, MRA, and angiography for optimum conservative or surgical management. BACKGROUND: Extrahepatic portal vein aneurysm is a rare clinical entity with no more than 50 reported cases in the English literature. METHOD: The clinical data of a patient with extrahepatic portal vein aneurysm were analyzed. RESULTS: Extrahepatic portal vein aneurysm associated with portal hypertension and splenomegaly was diagnosed by color Doppler ultrasonography (US), computed tomography (CT), magnetic resonance angiography (MRA) and angiography No hepatic encephalopathy and variceal bleeding occurred after the operation except mild pancreatic leakage caused by partial pancreatic tail resection. The patient recovered well. CONCLUSIONS: Extra hepatic portal vein aneurysm can be evaluated by US, CT, MRA , and angiography for optimum conservative or surgical management.