Myositis Ossificans

Myositis Ossificans is a condition where bone tissue forms inside muscle or other soft tissues after an injury. It mainly affects the musculoskeletal system, especially muscles near bones. This abnormal bone growth can cause pain, swelling, and limited movement in the affected area. It often develops after a traumatic injury like a muscle bruise or strain. The extra bone can make it difficult to use the muscle normally and may cause a hard lump under the skin. Over time, the condition may improve but can sometimes lead to lasting stiffness or discomfort.

Myositis Ossificans is a benign, heterotopic ossification disorder characterized by the formation of mature lamellar bone within skeletal muscle or soft tissues following trauma. It typically arises after muscle contusion, strain, or hematoma formation, leading to an aberrant repair process with fibroblastic proliferation and subsequent osteoid deposition. The condition is clinically significant due to its potential to cause pain, swelling, and restricted joint mobility near the affected muscle. Radiographically, it shows a characteristic zonal pattern of ossification with peripheral mature bone and central immature tissue. It is important to distinguish it from malignant soft tissue tumors such as osteosarcoma. The pathogenesis involves dysregulated differentiation of mesenchymal cells into osteoblasts triggered by local injury and inflammation.