Radiological features of an ossifying subperiosteal hematoma in a patient with severe motor and intellectual disability

Subperiosteal hemorrhage of the long bones occurs mainly in patients with various conditions attributed to abnormal collagen production, such as neurofibromatosis, scurvy, and copper deficiency, even though the preceding trauma is minimal [1-6]. It is also reported that hemophilia can be involved in this injury [7]. Subperiosteal hemorrhage often accompanies ossification, although the precise mechanism remains unclear [1-6]. Pathologically, mesenchymal cells proliferate from the wound periphery and migrate centripetally towards the lesion's center in the incipient phase. Then osteoid and bone are laid down from the periphery to the center, and finally matured bone and marrow fat are established [8, 9]. We report the case of a 16-year-old girl with severe motor and intellectual disability, presenting a massive ossifying subperiosteal hematoma of the right thigh following an epicondyle fracture of the right femur. Serial imaging features in this case demonstrate the pathological course of the ossifying subperiosteal hematoma.