Myositis Ossificans Associated With Subclinical Idiopathic Thrombocytopenic Purpura: Report of a Case

A 56-year-old healthy man noticed a stony-hard mass gradually grown in his neck for more than a 6-year period. Examinations revealed 2 additional calcified masses at the esophageal hiatus and retroperitoneum. The cut-surface of the operative specimens showed fibrous and mucinous appearance with many calcified islands. Microscopically, the lesion showed a gradual transform from the central immature area with fibroblasts and mucinous matrix, to the peripheral mature area with woven bone and osteoclasts (zoning phenomenon), which was compatible with the features of mature myositis ossificans. Myositis ossificans is an isolated, benign, nonneoplastic disease typically found in adolescence, after traumatic episode. Similar lesions have been found in the major musculature of patients with increased bleeding tendency. In the present case, idiopathic thrombocytopenic purpura was found to be associated and was suggested to be involved in initiating myositis ossificans. Still, it is extremely rare to observe lesions in these sites synchronously.