Primary intraosseous carcinoma of the jaws originating in odontogenic cysts.

Primary intraosseous carcinoma (PIOC) of the jaws is a rare lesion and majority of them arise from the epithelial lining of pre-existing odontogenic cysts (OCS). In a case of 20 year old male, PIOC presented a painless swelling extending from left posterior side of the mandible to across the midline with a duration of three months. X-rays revealed a cystic Unilocular radiolucency with well demarcated margin. Aspiration revealed the characteristics of cystic fluid. Histological examination of the biopsy specimen following marsupialisation showed SCA arising in cystic lining. In another case of 24 year old female, PIOC presented a painless swelling on the right side of the mandible with a hollow cavity seen intraorally in the region of the first molar, exfoliated itself in one month. X-rays revealed a cystic radiolucency but with irregular margin centrally. Histologic examination of a biopsy specimen from the lining of the cavity showed SCA originating in cystic lining. In both cases habit of tobacco was absent.