Diagnostic Utility of Ki-67 for Histopathological Typing of Conventional Ameloblastoma, Proliferative Ameloblastoma and Ameloblastic Carcinoma – A Retrospective Study

Abstract

BACKGROUND Ameloblastoma is a rare, benign odontogenic neoplasm which is locally aggressive and mostly present with a painless swelling. The enigma about the diagnosis of proliferative ameloblastoma and ameloblastic carcinoma is still a debate because the diagnostic criteria is not standardized or quantified which has a direct correlation on its biological behaviour and prognosis. Despite numerous studies, correlation between the histological patterns of ameloblastoma and tumour behaviour has not been consistently established. The present study was done to compare the expression levels of Ki-67 between conventional ameloblastoma, proliferative ameloblastoma and ameloblastic carcinoma and to assess the usefulness of these markers for diagnostic differentiation. METHODS A retrospective study of total of 18 cases of ameloblastoma were retrieved from the archives of Department of Oral and Maxillofacial Pathology, Saveetha Dental College from 2012 till 2019, which included conventional ameloblastoma, proliferative ameloblastoma and ameloblastic carcinoma. Immunohistochemical (IHC) analysis was done using the marker Ki-67 and labelling index were determined for the same. RESULTS The results of the current study showed that the cellular proliferative activity assessed using Ki-67 in follicular ameloblastoma was (55 %), 4 cases of plexiform ameloblastoma (22 %), 17 % of proliferative ameloblastoma and 6 % of ameloblastic carcinoma showed negative expression. CONCLUSIONS Immunophenotyping using the marker Ki-67 may be a useful tool for histological typing of ameloblastoma. KEY WORDS Ameloblastoma, Ki-67, IHC, Immunophenotyping