Evidence for proximal tubular cell origin of a sarcomatoid variant of human renal cell carcinoma.

A pure sarcomatoid variant of renal cell carcinoma obtained from a hydronephrotic kidney of an elderly white female was grown in tissue culture. Two parallel cell lines, one from the primary neoplasm and the other from a seeded metastasis within the same kidney have been cultured for more than 60 passages over a period of three years. Structural and functional studies of this neoplasm confirmed that it originated from proximal tubular cells.