Targetable Molecular Profiles in Salivary Duct Carcinoma: A Review and Case Study of Molecular Diagnostic and...

Salivary duct carcinoma is a rare, high-grade malignancy of the salivary glands, most commonly arising in the parotid. This review highlights recent advancements in the cytologic, immunophenotypic, and molecular characterization of salivary duct carcinoma, emphasizing the central role of biomarkers such as androgen receptor (AR) overexpression and ERBB2 (HER2) amplification in diagnosis, prognosis, and therapeutic decision-making. These principles are illustrated through the case of a 55-year-old male with AR-positive, HER2-amplified salivary duct carcinoma of the right parotid gland with nodal and osseous metastases. Diagnosis was established via fine-needle aspiration (FNA) cytology, immunocytochemistry, and molecular profiling. The patient underwent androgen deprivation therapy followed by treatment with a HER2 targeted antibody-drug conjugate, achieving disease stability. This case exemplifies how molecular diagnostics inform personalized treatment strategies in salivary duct carcinoma and underscores the need for standardized testing protocols and greater awareness of precision oncology approaches in salivary gland malignancies.