A rare case of primary aldosteronism due to bilateral functioning adrenocortical adenomas

Abstract

A 43-year-old man was admitted to our hospital in January, 1991 for further examination of polydipsia, polyuria and hypertension. He had had a personal history of hypertension since 1976 and of diabetes mellitus since 1982. Physical examination and routine laboratory studies showed that the patient was characterized by asymptomatic hypertension in the presence of hypokalemia and increased urinary potassium excretion. Plasma aldosterone concentrations (PAC) were elevated and plasma renin activity (PRA) was suppressed, resulting in a considerable increase in the ratio of PAC to PRA. PAC was not normally suppressed by saline infusion (2 1/2h, iv). PRA remained suppressed and PAC did not rise after stimulation with iv injection of furosemide (40 mg) in combination with walking for 60 min. PAC was increased in response to ACTH injection (0.25 mg, iv) but not suppressed by dexamethasone administration (2 and 8 mg/day, po). PAC did not rise after iv infusion of angiotensin II (20 ng/kg/min for 30 min). Venous sampling showed that PAC was considerably elevated in the bilateral adrenal vein. CT and MRI demonstrated tumor mass in the bilateral adrenal gland and the remaining normal portion in the left adrenal gland. Scintigraphic imaging with 133I-aldosterol during dexamethasone suppression provided bilateral uptake in the adrenals. Oral administration of spironolactone (375 mg/day) suppressed blood pressure and elevated PRA and serum potassium. Elevated PCA and PRA levels as well as hypertension were corrected by right-total and left-subtotal adrenalectomy performed in March, 1991. However, impaired glucose tolerance was not changed after surgery, and plasma glucose levels were well controlled with a small dose of insulin (9U/day). Pathological studies revealed adrenocortical adenoma cells of clear cell type with spironolactone bodies in the bilateral adrenal tumors. These findings indicate that this is a very rare case of primary aldosteronism due to bilateral functioning adrenocortical adenomas, which is accompanied by diabetes mellitus.