Dentigerous Cyst Associated with a Supernumerary Malformed Tooth: Report of a case and a clinicopathologic review.

Abstract

A case of a dentigerous cyst associated with a malformed supernumerary tooth is reported, and the clinicopathological characteristics of dentigerous cysts with abnormal dentition are reviewed from the literature and our hospital records. A 7-year-old boy had a painless and radiolucent lesion in his right molar region of the mandible. Radiographic examinations revealed that a well-defined cystic lesion, measuring 20 mm in diameter and containing a toothlike calcified structure, was located between the first and second molar tooth germs. Histopathologically, the cyst wall was composed of fibrous granulation tissue with a squamous epithelial lining. The calcified structure was a reversely concaved tooth crown which protruded into the cystic lumen with its enamel layer at the inner surface. The cyst lining epithelium was continuous with the reduced enamel epithelium covering the malformed tooth. A review of the literature and a case survey in our hospital showed that about 10% of dentigerous cysts were associated with supernumerary teeth which were mostly located in the median region of the maxilla, but that those in the mandibular molar region were extremely rare.