Aggressive calcifying odontogenic cyst--a possible variant of ameloblastoma.

A case of an aggressive calcifying odontogenic cyst of the maxilla is presented. It recurred twice after surgical excision over the course of a year and was subsequently treated by maxillectomy followed by radiotherapy. The current histological criteria for the diagnosis of calcifying odontogenic cyst were satisfied but it is argued that they are drawn too widely. Since the majority of calcifying odontogenic cysts are benign in behaviour the presence of cytological indicators of local destruction and invasiveness alongside the usual features of calcifying odontogenic cysts (presence of dentinoid, epithelial ghost-cell degeneration) should be the over-riding prognostic considerations and should thus be reflected in the diagnostic title. Such tumours are best regarded as variants of ameloblastoma rather than as unusually aggressive forms of calcifying odontogenic cyst and an appropriate name would be 'dentinogenic ghost-cell ameloblastoma'.