Renal cell carcinoma is a rare cancer in Thailand. Most of the patients present in advanced metastatic stage with identifiable renal mass. In this case report, we presents a case of male patient who manifested with supraclavicular lymph node enlargement and CT scan of chest and abdomen showed multiple sites lymph node metastasis but there was no primary mass detected anywhere. The pathology of supraclavicular lymph node was papillary cell adenocarcinoma. The differential diagnoses were papillary thyroid cancer, gastrointestinal tract carcinoma such as pancreato-biliary cancer, non small cell lung cancer, and renal cancer. Immunohistochemistry result were negative for TTF-1, Thyroglobulin, CD7 and CD20 which ruled out non-small cell lung adenocarcinoma, thyroid cancer and gastrointestinal tract cancer respectively. CD10, Vimentin and RCC were all positive and all are specific for renal cell carcinoma. The diagnosis was renal cell carcinoma, papillary cell type. Sunitinib, a tyrosine kinase inhibitor, is the treatment of choice for renal cell carcinoma since it improves objective response rate and shows longer progression free survival than IFNα.
Keywords: Lymph node metastasis; Renal cell carcinoma; Unknown primary cancer; Without primary site.