To the Editor.
—We would like to describe a patient who was found to have lateralizing renal vein renin activity during evaluation for a pheochromocytoma. No abnormality of the renal vasculature was found, a situation not previously described, to our knowledge.
Report of a Case.
—A 24-year-old man had had poorly controlled hypertension for two years, associated with palpitation, headache, nausea, vomiting, dizziness, diaphoresis, and weight loss. Urinary metanephrine, vanillylmandelic acid, and norepinephrine values were found to be markedly elevated. Angiography demonstrated a 6-cm right suprarenal mass and two normal renal arteries supplying each kidney (Figure). Selective venous sampling from the renal veins (simultaneously) and the inferior vena cava, below the renal veins, was performed. In the left renal vein, plasma renin activity (PRA) was 6.33 ng/mL/hr, norepinephrine value was 1,371 pg/mL, and epinephrine was undetectable. In the superior right renal vein, PRA was 13.33 ng/mL/hr, norepinephrine value was 4,843