Dentigerous Cyst and Ameloblastoma of the Jaws

To determine how many ameloblastomas were misdiagnosed as dentigerous cysts (DCs) by correlating the radiological and histopathological features of a series of both entities.

Histopathology reports and radiological imaging of 135 DCs and 43 ameloblastomas were reviewed. Any clinical or radiological feature that suggested that the diagnosis of DC was wrong-for example, absence of an unerupted tooth-prompted review of the original histology. A total of 34 cases coded as DC at diagnosis were excluded; in the remaining 101 patients, the clinicoradiological and histopathological features were consistent with DC in 96 (95.0%). Review of the histology revealed that 4 patients had actually had odontogenic keratocysts (OKCs) and one a luminal/simple unicystic ameloblastoma (UA). One other OKC and 3 other ameloblastomas (1 luminal UA, 2 solid/multicystic) had originally been diagnosed as DC; these had been identified prior to the study. Of the 9 misdiagnosed patients, 6 were ≤20 years old. Clinically, DC had been the only, or one of the differential, diagnoses in 7 patients; in the other 2, the clinical diagnosis was radicular cyst. In none of the 4 misdiagnosed ameloblastomas was the radiology compatible with a diagnosis of DC. Incorrect terminology had been used on the histopathology request form in 5 of the 34 excluded cases where the clinical diagnosis was DC, despite the cyst being periapical to an erupted carious or root-filled tooth.

The entire clinical team must ensure that a histopathological diagnosis of DC is consistent with the clinicoradiological scenario, particularly in younger patients.