Clear cell odontogenic carcinoma (CCOC) is a rare and aggressive malignant epithelial neoplasm, which occurs most frequently in the mandible of elderly patients. Morphologically, CCOC shares similar characteristics with other clear cell tumors, especially hyalinizing clear cell carcinoma of the salivary glands (HCCC). Both CCOC and HCCC are known to harbor EWSR1 rearrangements, especially the EWSR1-ATF1 gene fusion, which indicates a possible link between the two lesions. So far, this fusion has been demonstrated in five cases of CCOC in the literature. Herein, we add another CCOC case to the literature, which arose in the mandible of an 82-year-old female patient and was proven to harbor the EWSR1-ATF1 gene fusion. Immunohistochemically, this case was focally positive for CK7, CK14, CK19 and p63. The patient was referred to surgical treatment; however, she died of disease 2 months after the diagnosis, thereby demonstrating the aggressive nature of this tumor.

Background: Surgically assisted rapid maxillary expansion (SARME) generates an uncomfortable postoperative period accompanied by pain, edema, and paresthesia. There are few studies on the effect of photobiomodulation (PBM) after SARME and it was not possible to find studies on the efficacy of light emitted by diode (LED) after this type of intervention. The main objective of the study will be to evaluate the efficacy of PBM with LED in the control of pain, facial edema, paresthesia, and bone repair after SARME. Methods: A randomized, double-blind, placebo-controlled clinical trial involving 72 participants aged from 18 to 45 years, who search the Department of Buccomaxillofacial Surgery and Traumatology of Mandaqui Hospital Complex, will be conducted. Immediately after surgeries, the participant will be inserted into the placebo or LED group. In the LED group, the participants will receive PBM with an extraoral device (660 and 850 nm with 6 J per point) and an intraoral device (660 nm with 2 J per point) and in the control group the person in charge of the application will simulate the irradiation with the devices kept off. The applications will be in the immediate postoperative period, 1, 2, 7, 14, 30, 60, 90, and 120 days after the end of the surgeries, when the evaluations will also be performed. Facial measurements, extra and intraoral sensitivity, pain and bone repair will be evaluated. Secondarily, data regarding the occurrence of headache; otalgia; nausea; bruising; nasolacrimation; epistaxis; dysphagia; systemic and superficial temperature in the operated region; use of analgesics and anti-inflammatories; anxiety and impact of oral health on the participants’ quality of life will be computed. Discussion: Since PBM has shown positive effects on postoperative complications of other types of oral surgery and also has a positive effect on bone repair after maxillary disjunction, surgically assisted or not, it seems clear the need to evaluate its performance regarding pain, edema, and paresthesia after these surgeries. Trial registration: This protocol was registered in Clinical Trials platform (https://clinicaltrials.gov/) with the number NCT03814525, first published and last updated on January 24, 2019.