Bilateral epithelial-myoepithelial carcinoma: an extraordinary tumor of the paranasal sinuses.

A 54-year-old woman presented with a 6-month history of swelling on the right side of her face. On physical examination she was found to have a huge mass in the right nasal cavity. Magnetic resonance images of the paranasal sinuses revealed a soft tissue mass in the right maxillary sinus and a mass was also seen in the left maxillary sinus. On histopathologic examination, the tumor had a lobular structure with infiltrating margins. Two cell types, an outer layer of myoepithelial and an inner layer of duct-like cells, were found. On immunohistochemical examination, myoepithelial cells stained positively for calponin, p63, GFAP, S-100 protein, alpha-smooth muscle actin cytokeratin-14. The tumors were resected completely and no recurrence or metastasis was found 30 months after surgery. We describe here an unusual case of epithelial-myoepithelial carcinoma (EMC) arising from the paranasal sinuses. This is the first case report in the literature describing bilateral EMC in the maxillary sinuses.