Sebaceous epithelial-myoepithelial carcinoma of the parotid gland: a case report of a new histologic variant.

ABSTRACT

Epithelial-myoepithelial carcinoma (EMCa) is a double-cell layered low-grade malignant tumor, representing approximately 1% of all salivary gland tumors (Barnest et al. 2005 [1], Brocheriou et al. 1991 [2], Fonte et al. 2001 [3]). Its histologic characteristic is that of an inner layer of cuboidal epithelial cells with dense granular cytoplasm and central or basal rounded nucleus, and an outer layer of clear, polygonal myoepithelial cells, together forming ductal structures in a lobulated papillary or cystic pattern. Although solid components of clear cells are not uncommon, and squamous differentiation, spindle cells, and oncocytic appearance are well-documented histologic features of EMCa, sebaceous differentiation as a precise histologic variant has, to our knowledge, only been suggested by Shinozaki et al [4] in 2008. In this report, we present a case of a carcinoma of the parotid gland in a 59-year old female patient with an immunophenotype supporting the proposed entity of sebaceous EMCa.