parotid sebaceous epithelial-myoepithelial carcinoma

Epithelial-myoepithelial carcinoma (EMCa) is a double-cell layered low-grade malignant tumor, representing approximately 1% of all salivary gland tumors.

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 hasbeen suggested by Shinozaki et al. in 2008.

References

 Sebaceous epithelial-myoepithelial carcinoma of the parotid gland: a case report of a new histologic variant. Stålhammar G, Elmberger G. Ann Diagn Pathol. 2014 Aug;18(4):248-52. doi : 10.1016/j.anndiagpath.2014.04.004 PMID: 24929841