Mucoepidermoid carcinoma is a malignant tumor charaterized by the presence of epidermoid cells, mucus-producing cells, and cells of intermediate type. We report here a rare case of a clear-cell variant of mucoepidermoid carcinoma arising in the left maxillary sinus. A 51-year-old man visited our clinic because of swelling at the left side of the palate and the maxillary region. Magnetic resonance imaging revealed intermediate or high signal intensity on T1-contrast weighted images in the left maxillary sinus enhanced by Gd-DTPA. Our clinical diagnosis was a malignant tumor in the sinus. Subsequently, a biopsy specimen taken from the left sinus was diagnosed as “mucoepidermoid carcinoma.” Left hemimaxillectomy was performed. Microscopically, the tumor was composed of nests of numerous large clear cells, which stained positively with PAS stain, suggesting the presence of glycogen granules. Some features of mucoepidermoid caricinoma were observed, around the nests. The histological typing of mucoepidermoid carcinoma was therefore clear-cell variant. The prognosis is unclear; we are therefore closely following up the patient.
