A sixteen years old boy with hemophilia A was admitted in August 1981 with history of spontaneous pain in groin, paresthesia of the anterior and medial aspect of the thigh and paralyzed quadriceps muscle on the right side. On examination the hip joint was held in 35 degrees of flexion, the knee joint was held in 50 degrees of flexion and a small mass was felt in the right iliac fossa. Under use of antihemophilic factor, curettage of the pseudotumor in the iliopsoas muscle was carried out. The flexion contracture of the hip and knee joint was treated by conservative measures. On examination at ten months after the operation, the paralyzed femoral nerve recovered almost completely with improved range of motion of the hip and knee joint. The patient has been satisfied with little disturbance.
