RESUMO
A venous aneurysm is the dilation of a single communicating venous system, with or without an associated arteriovenous fistula. The literature documents a few cases of such aneurysms. A seventy-year-old man came to our hospital complaining of increased urinary frequency for the last few months, a left leg ulcer, and swelling of the left lower quadrant of the abdomen for 2 years. Doppler ultrasonography and CT angiography demonstrated a large external femoral vein aneurysm with arteriovenous fistula formation. Surgeons managed the case surgically, using a PTFE interposition grating to ligate the artery-vein connection. Early diagnosis and appropriate management are necessary to avoid fatal complications such as pulmonary embolism and aneurysmal rupture.