Atypical arteriographic features of myositis ossificans circumscripta (MOC).

Earlier reports on the angiographic features of MOC concluded that there may be hypervascularity and tumor stain but no A-V shunting, pooling, or vessel amputation as a result of the lesion. However, our cases demonstrated A-V shunting in MOC, and showed that the vascularity of this lesion can closely mimic that of malignant neoplasms. Therefore, the possibility of MOC should not be excluded because of the presence of A-V shunts or "tumor vessels" in suspected MOC lesion on plain radiography. These points are underscored by the findings in two MOC patients, whose cases are described.