Innocuous presentation of ameloblastic carcinoma

Ameloblastic carcinoma is a rare malignant odontogenic neoplasm that exhibits diverse clinical and radiological presentations. In fact there are several differential diagnoses during histopathological evaluation too. Lack of adequate reports could not establish the predominant demographic, clinical and radiological presentations. For the same reasons, the role of adjuvant radiotherapy and chemotherapy is also unsubstantiated yet. This case discusses the innocuous clinical and radiological presentation of ameloblastic carcinoma in a 55-year-old man where the diagnostic confirmation was achieved through histopathological evaluation. The differential diagnoses, treatment and follow-up details of this case are discussed in light of the previous published case reports and systematic reviews of case reports in an attempt to increase the sensitisation among dentists towards ameloblastic carcinoma.

Prognostic significance of SOX2 and GPC3 in Ameloblastoma and its malignant counterpart (Ameloblastic Carcinoma)

Background: Ameloblastoma is a common benign aggressive odontogenic tumor with a tendency for high recurrence rate. Ameloblastic Carcinoma is the malignant counterpart of Ameloblastoma. However, they are usually difficult to be distinguished from one another. Therefore, using Immunohistochemical markers might be beneficial for diagnosing them accurately.Objective: Evaluation of SOX2 and GPC3 expressions as well as evaluating their roles in the tumorigenesis and the biological behavior of Ameloblastoma and Ameloblastic Carcinoma.Methods: Tissue samples are composed of 34 archived histopathologically confirmed cases of (19 Conventional Ameloblastomas, and 15 Ameloblatic Carcinomas). Sections were subjected to Immunohistochemical staining according to a standard protocol by applying antibodies to SOX2, and GPC3.Results: SOX2 and GPC3 expressions in recurrent Ameloblastoma were significantly higher than non- recurrent cases. Ameloblastic Carcinoma showed the highest immune-reactivity to SOX2 and GPC3 compared to the Conventional Ameloblastoma. Desmoplastic Ameloblastoma showed the highest scores of SOX2 and GPC3 compared to the other subtypes.Conclusions: SOX2 and GPC3 can be used as a panel for diagnosing the aggressive and the malignant odontogenic tumors accurately. Desmoplastic Ameloblastoma behaves more aggressively than other Conventional Ameloblastoma subtypes.

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

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

Expression Profile of Stemness Markers CD138, Nestin and Alpha-SMA in Ameloblastic Tumours

Ameloblastic carcinoma is a rare malignant odontogenic neoplasm with a poor prognosis. It can arise de novo or from a pre-existing ameloblastoma. Research into stemness marker expression in ameloblastic tumours is lacking. This study aimed to explore the immunohistochemical expression of stemness markers nestin, CD138, and alpha-smooth muscle actin (alpha-SMA) for the characterisation of ameloblastic tumours. Six cases of ameloblastoma and four cases of ameloblastic carcinoma were assessed, including one case of ameloblastic carcinoma arising from desmoplastic ameloblastoma. In all tumour samples, CD138 was positive, whilst alpha-SMA was negative. Nestin was negative in all but one tumour sample. Conversely, the presence or absence of these markers varied in stroma samples. Nestin was observed in one ameloblastic carcinoma stroma sample, whilst CD138 was positive in one ameloblastoma case, one desmoplastic ameloblastoma case, and in two ameloblastic carcinoma stroma samples. Finally, alpha-SMA was found positive only in the desmoplastic ameloblastoma stroma sample. Our results suggest nestin expression to be an indicator for ameloblastic carcinoma, and CD138 and alpha-SMA to be promising biomarkers for the malignant transformation of ameloblastoma. Our data showed that nestin, CD138, and alpha-SMA are novel biomarkers for a better understanding of the origins and behaviour of ameloblastic tumours.