A 17-year-old boy fractures his left tibia in a skiing accident. One year later, an X-ray of the leg discloses reactive bone formation in the calf muscle at the site of injury. Which of the following is the most likely diagnosis?: (A) Myositis ossificans, (B) Fibrous dysplasia, (C) Malignant fibrous histiocytoma, (D) Nodular fasciitis
Answer is A. Myositis ossificans affects young persons and, although it is entirely benign, often mimics a malignant neoplasm. The lesion typically results from blunt trauma to the muscle and soft tissues, usually of the lower limb. Peripheral neovascularization of the resulting hematoma leads in a short time to the formation of bone spicules in the soft tissue because the local environment is similar to that of an initial hematoma in a healing fracture. Because myositis ossificans often occurs near a bone, on radiography, it may be misdiagnosed as a malignant bone-forming tumor. The other choices are unrelated to prior trauma.Diagnosis: Myositis ossificans