Pseudoaneurysm complicating osteochondroma is extremely rare. We describe a pseudoaneurysm in the popliteal fossa of a 21-year-old man, occurring 5 years after apparently incomplete resection of an osteochondroma at that site. We found magnetic resonance imaging and magnetic resonance angiography to be of great diagnostic value. Resection of the pseudoaneurysm and anastomosis of the popliteal artery were successful, with no recurrence detected for almost 7 years since the operation.
