Renin-producing renal cell carcinoma.

The pathogenetic relationship between tumor and hypertension was investigated in 40 patients with renal cell carcinoma. 15 of 40 patients were hypertensive. Four of these 15 patients with renal tumors and hypertension (26.7%) were found to have primary reninism. In these patients the plasma renin activity in blood from the renal veins showed a tumor kidney to contralateral kidney ratio of between 6 and 7. In the same 4 cases the renin content in the renal tumor tissue was significantly higher than that in tissue from the adjacent tumor-free renal cortex of the ipsilateral kidney. Immunocytochemical demonstration of renin in the tumor was only possible in these 4 cases. In 3 of these patients blood pressure returned to normal following nephrectomy; in the 4th case there was a drop in blood pressure after nephrectomy. Renin-producing renal cell carcinomas are an uncommon cause of renal hypertension. The differential diagnosis of hypertension should therefore also include renal tumor.