Renin-secreting renal tumour with severe hypertension. case report with tumour renin analysis, histopathological and ultrastructural studies.

A 25-year-old man presented with severe hypertension associated with hypokalemia, elevated plasma renin level and secondary hyperaldosteronism. Malignant phase hypertension and renal artery stenosis were ruled out, and a preoperative diagnosis of renin-secreting renal tumour was made on the basis of higher concentrations of renin in the left than in the right renal venous plasma in spite of normal findings on selective renal arteriography. By removal of the affected kidney the tumour was found and it had a very high content of renin. Following the operation the plasma renin level, serum aldosterone concentration and BP became normal. We present a histopathological description and an ultrastructural study of the tumour.