The difficulties of diagnosing myositis ossificans circumscripta in the paraspinal muscles of a human immunodeficiency virus-positive man: magnetic resonance imaging and temporal computed tomographic findings.

Myositis ossificans circumscripta (MOC) is an uncommon disease that has been reported to develop after trauma, burns, and infections, as well as in cases in which the pathogenesis is unknown. Although most cases of MOC develop below the clavicles, it has been reported in the head and neck area, where it primarily involves the muscles of mastication. To our knowledge, there have been only 4 previous reports of MOC affecting the paraspinal muscles. We report the fifth such case, which developed in a human immunodeficiency virus-positive patient, and describe the longitudinal imaging changes of MOC.