Salivary Duct Carcinoma : Immunohistochemistry
Salivary gland carcinomas are positive for CK7, EMA, CEA, and GATA-3 (nuclear staining). GCDFP-15 is focally positive. They are also HER-2, EGFR, and androgen receptor positive while ER and PR are negative. The Ki-67 proliferation index is usually high. This case showed squamous differentiation in the form of abundant eosinophilic cytoplasm, intercellular bridges and small keratin pearls.