Epithelial-myoepithelial carcinoma arising in the oral floor: Report of a case and review of the literature

Epithelial-myoepithelial carcinoma (EMC) is an extremely rare low-grade malignant salivary gland tumor that most commonly occurs in the parotid gland, but can also arise in minor salivary glands. We report here a case of EMC localized in oral floor in a 66-year-old female who presented with left side of oral floor swelling of four years duration. CT scan revealed a nonhomogeneously enhancing mass in the left side of the oral floor extending to the midline of the oral cavity. After establishing a clinical diagnosis of a benign tumor arising in the left side of oral floor, a biopsy of the lesion was performed under local anesthesia. The histological diagnosis was suspected pleomorphic adenoma, however, it could not deny the possibility of malignancy, because of that there were any evidence of nuclear atypia or mitotic figures. Then, the patient underwent a wide local excision, where was realized immunohistochemical analysis, staining the duct-like structures, where the inner layer of epithelial cells positively for AE1/AE3 and CK 14, whereas outer layer of myoepithelial cells stained positively for calponin and vimentin antibodies. Based on these findings, the final histological diagnosis was EMC. The patient was discharged from the hospital, and she is being followed up about 5 years without evidence for neither recurrences nor metastases.