A clinical and histopathological study of cysts with keratinized epithelium in the jaws

Odontogenic keratocyst is considered to be a synonym for epidermoid cyst of the jaw in Europe and the United States. In Japan, Eda et al. first described odontogenic keratocyst in 1972. They claimed that previously reported cases of epidermoid cysts of the jaw could be included in this category. However, these two diseases are often treated as separate entities. The authors conducted a detailed clinical and histological study of 16 patients (15 with odontogenic keratocysts and one diagnosed as having epidermoid cysts of the jaw in 1971) to investigate the presence of epidermoid cysts of the jaw. The results of this study were compared with those in 48 patients with 54 cysts who were reported to have had epidermoid cysts of the jaw during the 60 years from 1931 to 1990 in Japan to retrospectively study cases previously reported in the literature. Fifteen patients who were diagnosed as having odontogenic keratocysts during the 14 years from 1979 to 1992 and one patient who was diagnosed as having epidermoid cysts of the jaw in 1971, all of whom were diagnosed in our department, were analyzed in regard to compatibility with the histopathological criteria for odontogenic keratocysts described by Pindborg et al. in 1963. All cysts were compatible with the criteria. An analysis of the 48 patients with a total of 54 epidermoid cysts of the jaw that were previously reported in Japan showed that these cysts were similar histopathologically to the odontogenic keratocysts described by Pindborg et al. Clinically, the former cysts did not apparently differ from the latter cysts. It was difficult to distinguish the majority of previously reported cases of epidermoid cysts from odontogenic keratocysts.