Supraclavicular lymph nodes: An easily accessible site for diagnosis and molecular profiling of malignancies in the era of precision medicine.

BACKGROUND: The supraclavicular lymph node (SCN) is a common metastatic site for malignancies of supra and infra-diaphragmatic origin and is easily accessible for small biopsy and fine needle aspiration (FNA). In this study, the utility of SCN biopsies was analyzed for diagnosis and ancillary studies.

METHODS: The electronic pathology archive was searched for cases of FNA of SCNs accompanied by small core biopsies (1/2016-12/2018). The patients' demographics, diagnosis, and ancillary studies were recorded.

RESULTS: Eighty-eight cases were reviewed (49 females and 39 males), with patients' ages ranging from 23 to 84 years (mean = 52.85 years). Fifty-four (61.4%) specimens were from the left SCN and thirty-four (38.6%) from the right. All FNA cases were performed by a radiologist under ultrasound guidance and rapid on-site evaltion (ROSE) was performed by a cytologist. Nineteen cases (21.6%) were benign and sixty-nine cases were malignant (78.4%). Carcinoma was the most common malignant neoplasm (52.3%) including 38.2% (13/34) of the right SCN and 61.1% (33/54) of the left SCN cases. Metastatic lung and breast adenocarcinomas (9.1% each) were the most common carcinomas overall. Lymphoma was the second most common malignancy (17.0%) including 17.6% (6/34) of the right SCN and 16.7% (9/54) of the left SCN cases. The majority of cases were accomponied by ancillary studies for diagnosis and prognostic markers. Ancillary studies included immunostains (63 cases, 71.6%), PD-L1 testing (21 cases, 23.9%), FISH testing (7 cases, 8.0%), flow cytometry (20 cases, 22.7%) and NGS studies (8 cases, 9.1%).

CONCLUSION: Supraclavicular lymph nodes are easily accessible and diagnostically useful sites for detection of malignancies and molecular alterations responsive to targeted or immune therapy.