Primary cancer of the kidney is derived from three principal sources: (1) tubular epithelium, which gives rise to adenocarcinoma; (2) epithelium lining the pelvicalycine system, from which transitional cell carcinomas develop; and (3) immature parenchymal tissue, the source of the Wilms' tumor or nephroblastoma. Malignant tumors also occasionally arise from mesodermal elements within the kidney, but these comprise only a small proportion of all malignant renal neoplasms. The commonest tumors are those which develop from mature tubular epithelium, and it is with these that the present account is concerned. "Renal adenocarcinoma" is probably the most convenient term, although the histologic structure of such tumors is extremely variable and classic adenomatous patterns may be difficult to discern. Other terms—eg, hypernephroma, Grawitz's tumor, malignant nephroma, metanephroma—have nothing to commend their use.
Renal adenocarcinoma is more frequent in males, occurring most commonly during the fifth and sixth decades. The tumor shows no consistent