Hybrid Carcinoma of the Parotid Gland: An Extremely Rare Three Cases with an Immunohistochemical Analysis and a Review of the Literature

Abstract

Salivary hybrid carcinoma (HC) is defined as when two or more kinds of carcinoma exist at the same location in a single mass. We reestimated and examined three cases of salivary gland HC. Case 1 involved a 76-year-old male. Case 2 involved a 74-year-old female. Case 3 involved a 66-year-old male. Histologically, case 1 involved a combination of salivary duct carcinoma (SDC) and squamous cell carcinoma (SqCC). Immunohistochemically, the former was positive for gross cystic disease fluid protein (GCDFP)-15 and androgen receptor (AR). Case 2 involved a combination of SqCC and neuroendocrine carcinoma. Immunohistochemically the latter was positive for synaptophysin and neural cell adhesion molecule (NCAM). Case 3 involved a combination of SDC and epithelial–myoepithelial carcinoma (EMC). Immunohistochemically, the former was positive for GCDFP-15 and AR, whereas the inner cells of the latter were positive for cytokeratin 7, and the outer cells of the latter were positive for actin. Because of the transitional zone between SDC and EMC, it was speculated that high-grade SDC arose from low-grade EMC.

Apocrine epithelial-myoepithelial carcinoma with phyllodes-like morphology of the parotid gland: A case report of an unusual histology with immunohistochemical and genetic analyses using next-generation sequencing

“…The inner ductal cells of the apocrine EMC were morphologically and immunohistochemically similar to those of the ductal cells of SDC. Hybrid carcinomas, which are composed of EMC and SDC, have rarely been reported [27][28][29]. Therefore, our case was subclassi ed as an apocrine EMC.…”