Role of fine needle aspiration cytology in the management of supraclavicular lymph node metastasis: Review of our experience.

INTRODUCTION: In the 19th century Virchow described that metastasis to left supraclavicular lymph nodes (SLN) could originate in neoplasms located under the diaphragm. In the same way, right SLN metastasis are usually thought to arise from thoracic neoplasms. Our aims are to review our experience with metastatic SLN diagnosed by fine-needle aspiration cytology (FNAC) and to discuss the location of the primary in these cases. METHODS: We have reviewed all lymph node FNACs diagnosed in a single tertiary hospital between 2010 and 2017 and we have included all cases of metastatic SLN. RESULTS: We have found 57 cases of SLN FNAC with a diagnosis of malignancy, 39 of which had no previous diagnosis (17 left, 20 right and 2 bilateral SLN). The most frequent diagnosis were adenocarcinoma, squamous cell carcinoma and small cell carcinoma. Right and bilateral SLN showed mainly lung metastasis. Left lesions were more widely distributed, with 11 originating in the lung, followed by the breast, gastroesophageal junction and prostate gland. In two cases, the primary origin was not identified. In SLN with metastasis of a known origin, the main source of the tumor was again the lung and only one case originated in the stomach (left SLN metastasis). CONCLUSIONS: The origin of SLN metastasis seems to be dependent on both the frequency of tumor types in each geographic area and tumor location. Left SLN are more frequently involved by infradiaphragmatic primary tumors, while right SLN are exclusively involved by supradiaphragmatic neoplasms.