Calcification in epulis osteoplastica

As we experienced a rare case of large epulis fibrosa osteoplastica which arose from the upper jaw of a 35 year-old male, we studied biologically and morphologically using this epulis.The tumor, 30×20×20 mm in size, located in the muco-gingival region of the bridge (765) and connected with a stalk to alveolar gingiva under the dummy of the bridge.Radiograph revealed radiopaque spots which indicated the existence of calcified substances.The tumor was surgically removed and investigated both morphologically and biochemically.The histopathological findings showed that there were immature woven bones surrounded by osteoblasts and prominant proliferation of fibrous connective tissue between epithelium and woven bones.Biochemical studies demonstrated that acid soluble calcium and phosphorus contents were relatively high corresponding with the region of bone formation. At this region alkaline phosphatase activity and inorganic phosphorus ion were also increased.These results suggest that the woven bones in epulis are calcified, and that both the increases of alkaline phosphatase activities and inorganic phosphorus ion contents may contribute to the onset of calcification.