Mucoepidermoid carcinoma of the maxillary sinus is rare. We describe a poorly differentiated mucoepidermoid carcinoma originating from the right maxillary sinus of a 65-year-old woman. On presentation, she complained of pus discharge from the right nasal cavity and facial swelling with deformity. Radiographic studies, including a CT scan, suggested a tumor-like image with destruction of the right maxillary sinus. After intraoral opening of the antrum, a histopathological diagnosis of poorly differentiated mucoepidermoid carcinoma was made. The patient received chemotherapy and radiotherapy, but the outcome was poor. The clinical course is described in detail in the text.
