There are many case reports about cysts within the bones of the jaws associated with impacted third molars. When osmotic pressure is introduced into a cyst, the cyst expands and displaces the third molar. If continuity of cyst wall is lost, cystic expansion cannot occur, and the cyst cannot displace the third molar. This study analyzed four cases of pathologic migration of the third molar in ruptured cystic lesions that had formed bone tunnels and intraoral fistulas to identify the causes and factors contributing to this migration. Authors hypothesized that closure of fistulas repeated generation of pressure, it may temporarily increase the osmotic pressure within a cyst that has lost its continuity, causing displacement of the third molar. A cyst that has lost its continuity due to fistula formation within the oral cavity can cause ectopic displacement of the adjacent impacted teeth.

Whereas calcium deposition in soft tissues is not uncommon, highly-structured, identified as mature cancellous bone within soft tissues is not frequent. Here, we report an usual case of mature cancellous bone in cheek subcutaneous tissue in 15-year-old Korean male. Microscopically the cancellous bone was encompassed by epithelial cells, which was confirmed by immunohistochemical staining with cytokeratin AE1/3. The present mature cancellous bone in subcutaneous tissue could be originated from oral epithelium.