RESUMEN
INTRODUCTION: Portal vein aneurysms are rare, representing 3% of venous aneurysms, with about 200 cases described in the literature, probably underestimated. CASE REPORT: A 66-year-old man, suspect of splenomegaly, underwent an abdominal ultrasound and a thoraco-abdomino-pelvic CT scan showing a 40mm portal vein aneurysm. Final diagnosis was T-cell hemopathy. Five and six months later, abdominal imaging was stable, suggesting congenital origin due to lack of obliteration of the vitelline vein. CONCLUSION: Portal vein aneurysms are often asymptomatic and an incidental finding. Monitoring is recommended because of their potential complications (thrombosis, rupture of aneurysm, portal hypertension, adjacent organs compression), annually if asymptomatic or more frequently with sometimes a surgical management in case of clinical manifestations.