A series of 240 odontogenic keratocysts: Should we continue to use the terminology of 'keratocystic odontogenic tumour' for the solid variant of odontogenic keratocyst?

Most of the odontogenic keratocysts show an indolent behaviour like non-neoplastic lesions. For this reason, the odontogenic keratocyst was reclassified within the odontogenic cysts category in the WHO 2017 classification. Some odontogenic keratocysts may contain satellite cysts or solid squamoid islands within their wall. Recently, a solid form of odontogenic keratocyst has also been described which is composed entirely of multiple epithelial islands and small cysts in a collagenous stroma. The true nature of this variant is unclear yet. In this article, we present a series of 204 odontogenic keratocyst cases. Clinical and histologic findings of the cases in this series were described. These were also categorised according to the presence of satellite lesions. Additionally, the features of two cases of the solid form of odontogenic keratocysts were compared with those of the previous reports and other histologically similar odontogenic lesions. Current evidence suggests that this variant may be neoplastic and it differs from other odontogenic keratocysts, at least histologically. We believe diagnosing a solid lesion as a cyst is counterintuitive and the term "keratocystic odontogenic tumour" better describes this particular variant. (C) 2018 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.