Pseudo-aneurysm of the popliteal artery by femoral exostosis in a young child.

Exostosis is a solitary benign bone tumor frequently observed in children. It may be totally quiescent or provoke complications. We report a case of pseudo-aneurysm of the popliteal artery caused by an exostosis on the lower metaphysis of the femur in a 12-year-old boy. This unusual complication mostly reported in young males (mean age 19 years) occurs in the context of an initial trauma in half the cases. Surgical treatment is a semi-emergency requiring both bone and arterial repair. Preventive surgery should be discussed for all cases of exostosis with a risk of arterial damage due to the gravity of the potential vascular complications.