New classification of maxillary ameloblastic carcinoma based on an evidence-based literature review over the last 60 years

BACKGROUND: The ameloblastic carcinoma is a rare malignant odontogenic tumor which rather occurs in the mandible than in the maxilla. Its rarity and in this context somewhat speculative histopathogenesis may account for diagnostic difficulties. Current classifications do not consider benign histopathological features at the primary and malignant features at the metastatic tumour site. Based on an evidence-based literature review, a recommendation for a novel classification is presented. METHODS: An evidence-based literature review over the last 60 years regarding ameloblastic carcinoma of the maxilla was conducted. RESULTS: An overall of 26 cases were found (mean age: 54.4 (5-83 years); male to female ratio: 2.7 to 1). In 54% the primary diagnosis was ameloblastic carcinoma, 34.6% revealed pulmonary metastases, however, only in one patient cervical lymph node metastasis could be found. Whereas two cases did not reveal malignant histopathology at the primary, they revealed malignant features at their metastatic sites. Nineteen of 26 patients (73,1%) were controlled during a median follow-up time of 54,3 months (6 to 156 months); 6 patients died of disease after a median time of 62,7 months (7 to 156 months) after initial diagnosis. CONCLUSION: It is of utmost importance to be aware of that ameloblastomas may be capable to degenerate into a "malignant" disease with recurrence and metastasis. In addition to local long-term control, special attention should be paid to potential pulmonary involvement.