Post-traumatic myositis ossificans: a benign lesion that simulates malignant bone and soft tissue tumours

Myositis ossificans (MO) is a benign bone formation in an extra-skeletal location. The most common subtype of MO, the post-traumatic, usually develops in young males after a traumatic event or sports injury. MO may simulate malignant bone lesions such as extra skeletal or surface osteosarcomas, or soft tissue sarcomas such as synovial sarcoma or undifferentiated pleomorphic sarcoma. In the early phase the diagnosis of MO is challenging because imaging and histopathological findings may be non-characteristic. Detailed medical history as well as clinical examination, follow-up imaging studies and histological assessment are crucial for a proper diagnosis. Early and accurate differential diagnosis between MO and malignant soft tissue and bone tumours is important to maximize.