A case of mucoepidermoid carcinoma associated with maxillary cyst.

We report a case of a mucoepidermoid carcinoma associated with a maxillary cyst. The patient was an 18-year-old man presenting with the chief complaint of left buccal swelling. The left maxillary third molar was semi-impacted in the direction of the crown on the buccal side. Orthopantomography revealed a cystic radiolucency extending over a wide area, ranging from the left maxilla to the maxillary sinus and nasal cavity. Computed tomography revealed a multilocular lesion surrounded by a thin shell of bone. Biopsy findings revealed a cystic lesion, but the cause could not be identified preoperatively. The cystic lesion was resected under general anesthesia. The lesion was multilocular and surrounded by a bone shell, and had expanded into the maxillary sinus. At the same time, indurated soft tissue adhering strongly to the palatine bone on the inferior palatine side of the lesion was resected. Histopathological examination showed a cystic lesion and mucoepidermoid carcinoma. An additional resection was planned and the maxilla partially resected. Mucoepidermoid carcinomas usually occur in the parotid and minor salivary glands, but in rare cases appear in the center of a jaw bone, almost always in the mandible. In the present case, the carcinoma was associated with a cystic lesion believed to have developed from maxillary bone and involved an impacted tooth adjacent to the tumor. This suggested a central mucoepidermoid carcinoma in the maxillary cyst. Postoperatively, the missing teeth have been replaced with a denture and the course has been good, with no recurrences or metastases identified.