Myositis Ossificans - Clinical
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Clinical Presentation: Myositis ossificans (MO) usually occurs in physically active, athletic adolescents or young adults (mean age 32 years) with a strong male predilection. It is rare in small children. Usually, there is history of recent soft tissue trauma or repetitive minor trauma. Some patients don't recall trauma but may report unusual muscle exertion.
There is rapid onset (within 1-2 weeks after trauma) with pain/tenderness, soft tissue swelling and edema at the site. The lesion becomes well-defined and firmer by the 2nd or the 3rd week. Examination reveals a hard nodular mass which may limit the range of motion of a nearby joint. Compression of adjacent neurovascular bundles can result in paresthesia, weakness, lymphedema or thromboembolic phenomena. Eventually, the pain disappears as the lesion matures (>8 weeks) and becomes mineralized.
Sites: MO can develop anywhere but is usually found in locations that are susceptible to trauma, such as the skeletal muscles of thigh (quadriceps), buttock (gluteal muscles), shoulder, and elbow (brachialis). Some cases involve muscles of head and neck region such as masseter temporalis and sternocleidomastoid. Similar lesions can also develop within subcutaneous fat or tendons/fascia and are referred to as panniculitis ossificans and fasciitis ossificans respectively. Rare cases arise in the mesentery following abdominal surgery or trauma and cause bowel obstruction.
Slide courtesy of Piero Picci, M.D., Director, Laboratory of Experimental Oncology, Instituto Ortopedico Rizzoli, Bologna, Italy. Used with permission.
There is rapid onset (within 1-2 weeks after trauma) with pain/tenderness, soft tissue swelling and edema at the site. The lesion becomes well-defined and firmer by the 2nd or the 3rd week. Examination reveals a hard nodular mass which may limit the range of motion of a nearby joint. Compression of adjacent neurovascular bundles can result in paresthesia, weakness, lymphedema or thromboembolic phenomena. Eventually, the pain disappears as the lesion matures (>8 weeks) and becomes mineralized.
Sites: MO can develop anywhere but is usually found in locations that are susceptible to trauma, such as the skeletal muscles of thigh (quadriceps), buttock (gluteal muscles), shoulder, and elbow (brachialis). Some cases involve muscles of head and neck region such as masseter temporalis and sternocleidomastoid. Similar lesions can also develop within subcutaneous fat or tendons/fascia and are referred to as panniculitis ossificans and fasciitis ossificans respectively. Rare cases arise in the mesentery following abdominal surgery or trauma and cause bowel obstruction.
Slide courtesy of Piero Picci, M.D., Director, Laboratory of Experimental Oncology, Instituto Ortopedico Rizzoli, Bologna, Italy. Used with permission.