Tamm Horsfall protein expression by a small renal cell carcinoma presenting with metastases

The clinical presentation of cervical metastases in a young woman presenting with cervical lymphadenopathy is described. The clinical, histological, ultrastructural and immunological findings establishing the diagnosis of a renal primary tumour are seen. The significance of mixed tumour cell expression of antigens specific for the proximal tubule (CD10, DPP4 and aminopeptidase N) and of Tamm Horsfall protein, normally expressed on the thick ascending limb of loop of Henle and distal tubule, is discussed.