Myositis ossificans of the foot.

A 37-year-old woman with myositis ossificans of the left foot is reported. A faint density was seen on foot radiographs, whereas computed tomography images showed a rim of mineralization inferior to the second and third metatarsal bones. On short tau inversion recovery-weighted magnetic resonance images, a hyperintense lesion was demonstrated with hyperintensity extending to the surrounding soft tissues. The rim of ossification appeared hypointense. Other non-neoplastic soft tissue processes with bone formation such as pseudomalignant osseous tumor of soft tissues, florid reactive periostitis, and bizarre parosteal osteochondromatous proliferation occur more commonly in the foot than myositis ossificans. A differential diagnosis of these lesions including periosteal and parosteal osteosarcoma, periosteal chondroma, and osteomyelitis is discussed.