Maxillary calcifying epithelial odontogenic tumor with sinus and buccal vestibule extension: a case report and immunohistochemical study

Background: Calcifying epithelial odontogenic tumor (CEOT) is a rare benign neoplasia, locally aggressive, that tends to invade bone and adjacent soft tissues. This case report describes the thirteenth known case of CEOT with maxillary sinus extension and the second one that also involves the buccal vestibule mucosa with peculiar histopathological and immunohistochemical data. Case presentation: Here we report the case of a 45-year-old female with a CEOT diagnosed and treated at the Oral & Maxillofacial Surgery Department, County Clinical Emergency Hospital of Craiova, Romania. The clinical and imaging investigation revealed an intraosseous tumor developed from the left posterior maxilla with maxillary sinus and buccal vestibule mucosa extension. Histopathology found an epithelium-rich CEOT variant, but with scattered S100 positive clear cells, focal small rounded cementum-like deposits and areas with some degree of nuclear pleomorphism. The immunohistochemical investigations emphasised its local aggressiveness behavior with involvement of multiple molecular mechanisms that underlie tumor invasiveness. A subtotal maxillectomy was performed followed by defect reconstruction. Conclusions: We discuss the relevant clinicopathological features of an aggressive rare case of CEOT with maxillary sinus extension and buccal vestibule mucosa involvement. The immunohistochemical study suggests its utility in attempting to assess the degree of local tumor aggressiveness and thus in adopting the most efficient therapeutic attitude.