Myositis ossificans circumscripta occurs in patients who have experienced trauma, especially in their arms or thighs. Certain hereditary abnormalities also cause MO.
MO presents as a rapid enlargement and significant pain in a muscle, one to two weeks after injury. Symptoms include swelling and warmth at the site as well as an increased ESR and serum alkaline phosphatase.
Appearing two to four weeks after injury on film, the tumor presents with increasing calcification in the periphery towards the center, along with increased uptake.
treatment consists of making the correct diagnosis, avoiding the potential incorrect diagnosis of cancer or infection, supportive treatment for pain, and treatment designed to minimize the calcification of the muscle.