False aneurysm of the femoral artery due to an osteochondroma.

Two cases of primary misdiagnosis of a posttraumatic false aneurysm are reported. In the first case a twenty-year-old patient was hospitalized under the diagnosis of a malignant soft tissue tumor five weeks after a kick against the right distal thigh. Diagnostic procedures performed in our clinic, however, led to the expectation of a false aneurysm of the femoral artery, caused by perforation of the wall of the vessel by an osteochondroma. Intraoperative findings confirmed this and led to the supposition of a connection with the mechanical trauma. The postoperative course was uneventful. The second case had a similar history. Prophylactic excision of osteochondromas in areas with increased risk of perforation, as in the region of the femoropopliteal junction, is recommended.