Epithelial myoepitheial carcinoma of minor salivary gland--low grade malignant tumor presenting with nodal metastasis.

ABSTRACT

Epithelial myoepithelial carcinoma (EMC) is a rare low grade malignant salivary gland neoplasm that most commonly occurs in the parotid gland but can also arise in minor salivary glands. We report a case of primary epithelial myoepithelial carcinoma of minor salivary gland in a 25 year old women who presented with swelling left cheek of one year duration and bilateral submandibular lymphadenopathy. A mass causing erosion of mandible, thyroid cartilage and masseter muscle was identified on CT scan. This was excised and histological examination revealed a mixture of ductal structures consisting of inner dark cells and outer clear cells seen in solid sheets. Immunohistochemical analysis showed the clear cells to be weakly positive for S100 and smooth muscle actin (SMA) and ductal cells to be positive for cytokeratin (CK) and epithelial membrane antigen (EMA). The characteristic morphological and immunohistochemical features aided in the diagnosis of epithelial myoepithelial carcinoma.