False popliteal aneurysm caused by exostosis of the femur.

A 45-year-old woman with a false aneurysm of the left popliteal artery caused by an exostosis of the femur is described. The patient had a tender swelling in the distal part of the thigh and a soft-tissue tumor was initially suspected. Diagnosis was made by ultrasonography, plain X-ray and angiography. The aneurysm and exostosis were resected. The literature regarding this condition is reviewed. Surgical treatment of popliteal aneurysm is recommended mainly because of the risk of occlusion of distal vessels by peripheral embolism.