Myositis ossificans—a rare tumor of the chest wall

Myositis ossificans (MO) is the abnormal formation of benign heterotopic bone tissue in soft tissues or muscles, mostly in sites of trauma. Though it has been described in most parts of the body, less than a dozen cases involving the chest wall have been reported. It is known to resolve spontaneously and various medical treatments have been suggested to hasten its resolution. Large tumors, suspicion of malignancy, and presence of symptoms are indications for surgical intervention. The differential diagnoses include sarcomas, infections, callous, calcified hematomas, and cysts. We present the clinical, radiological, and pathological images of a post traumatic MO of the chest wall, arising from under the medial third of the clavicle and growing into the deeper surface of the pectoralis major muscle. The patient is doing well eight months after the excision of the same.