Renin-secreting clear cell carcinoma of the kidney.

A young woman with mild to moderate hypertension and normal PRA, serum potassium levels, and urinary aldosterone excretion rate was found to have a renal tumor by selective renal arteriogram. Renal vein renin activity indicated an increased production of renin from the kidney containing the tumor. At surgery, a clear cell carcinoma of the kidney was found that contained renin activity in excess of the surrounding kidney tissue. The renin activity appeared identical to human kidney renin. Previous renin-producing tumors have been associated with severe hypertension, elevated plasma renin activity, hypokalemia, and elevated urinary aldosterone excretion. This case should call attention to the renin-secreting tumor as a cause of even mild hypertension.