Thrombosed Popliteal Artery Pseudoaneurysm as Herald of Tibial Osteochondroma

BACKGROUND Osteochondroma is the most common non-malignant tumour of bone, accounting for approximately one third of benign lesions in the skeleton. They often develop around the knee in the distal femur and in the proximal tibia and fibula. They present as a painless slow growing mass during adolescence and have been reported to cause damage to adjacent structures such as blood vessels; arterial damage is more common than venous injury and is usually a result of compression, stretching, and rubbing of the arterial wall. Such lesions include stenosis, thrombosis, and pseudoaneurysm formation possibly causing lower limb claudication or acute limb ischemia. METHODS An 18 year old male patient with a 4 week history of pain, hematoma, and oedema of the left calf without previous trauma is reported. A computed tomography scan (CT) revealed a large popliteal artery pseudoaneurysm and its close relationship to a protrusion of the proximal tibia. RESULTS The popliteal artery was repaired by an external saphenous patch and the exostosis was removed. The patient had palpable popliteal and distal pulses after surgery and during the first year follow-up. CONCLUSIONS Tibial osteochondroma should be considered in the differential diagnosis in young patients, among the potential causes of pseudoaneurysm of the femoral or popliteal artery. Surgical repair should be performed to restore normal blood flow with resection of the exostosis to prevent recurrence.