Salivary Duct Carcinoma: An Aggressive Salivary Gland Carcinoma with Morphologic Variants, Newly Identified Molecular Characteristics, and Emerging Treatment Modalities.

Salivary duct carcinoma (SDC) is a rare, aggressive salivary gland malignancy with significant mortality. Morphologically, most tumors are characterized by apocrine differentiation with a typical immunophenotype of androgen receptor positive/gross cystic disease fluid protein positive/estrogen receptor negative/progesterone receptor negative. Several morphologic variants of SDC exist, representing diagnostic pitfalls. Several differential diagnoses should be considered because prognosis, treatment, and management may be different from SDC. For SDC, current treatment strategies are aggressive and commonly include surgical excision with lymph node dissection and adjuvant radiotherapy. Continued research is examining the utility of androgen deprivation therapy and targeted molecular therapy.