Correspondence to: R Desai, Department of Pathology, Hospital for Joint Diseases, Orthopaedic Institute, 301 E. 17th Street, New York, NY 10003, USA formities were observed. No bruits were heard on auscultation. Neurovascular examination and laboratory findings were completely within normal limits. Plain radiographs of the thigh revealed an irregular 3.5-cm lesion of punctate radiodensity without zoning or cortical erosion, sited in the vastus lateralis muscle (Fig. 1). Magnetic resonance imaging demonstrated a well-defined mass with a lace-like structure of intermediate signal on proton density images (Fig. 2A). T2weighted images demonstrated a high-signal-intensity mass with lowsignal-intensity lace-like structures within the mass (Fig. 2B). Radiological findings were consistent with myositis ossificans. Other differential diagnosis included were benign or malignant soft tissue tumor with ossification. He underwent exploration and wide radical resection of the soft tissue mass. The mass was not attached to the bone or periosteum. Gross examination of the specimen demonstrated a segment of skeletal muscle, containing an ill-defined multilobulated red-brown vascular lesion measuring 3.5x2.5x2 cm with irregularly shaped bone trabeculae in the center. The blood-filled vascular spaces, of varying size, were traversed by streaked fibrosis and appeared to