Salivary Duct Carcinoma: Report of an Advanced Challenging Case Diagnosed by Ultrasound-Guided Fine-Needle Aspiration Biopsy.

We report a rare case of salivary duct carcinoma (SDC) in a 67-year-old male who presented with a rapidly enlarging, ill-defined left upper neck mass, accompanied by both cervical and axillary lymphadenopathy. Initial punch biopsy of the neck mass suggested metastatic breast carcinoma. However, ultrasound-guided fine-needle aspiration (US-FNA) and comprehensive immunohistochemical analysis, in conjunction with radiologic findings, confirmed the diagnosis of SDC. This case highlights the diagnostic challenges of SDC and reinforces the pivotal role of US-FNA cytology in establishing a definitive diagnosis while minimizing invasive procedures.