Hyperplasia of renin-containing cells in a malignant pheochromocytoma: an immunohistochemical and semiquantitative study.

The renin-containing cells in the kidneys of a patient with malignant pheochromocytoma were investigated immunohistochemically. Elevated plasma renin and catecholamine levels were detected during the clinical course. Remarkable hyperplasia of renin-containing cells was observed in the afferent arterioles and interlobular arteries. Semiquantitative assessment was performed to compare this case with cases of renovascular hypertension, with one case of malignant nephrosclerosis, and with six cases without hypertension. The grade of hyperplasia of renin-containing cells in pheochromocytoma was similar to that in renovascular hypertension and was different from that observed in control cases. Histologic examination of the kidneys revealed neither stenosis of the renal arteries nor ischemic changes of glomeruli. Direct stimulation of renin-containing cells by catecholamines is suggested as the cause of the hyperplasia. This is the first morphologic demonstration of hyperplasia of renin-containing cells in pheochromocytoma.