BILATERAL ALDOSTERONE-PRODUCING ADENOMAS IN 2 PATIENTS DIAGNOSED BY IMMUNOHISTOCHEMICAL ANALYSIS OF STEROIDOGENIC ENZYMES

Bilateral adrenal aldosterone-producing adenomas (APA) are rare. It is important to distinguish bilateral APA from idiopathic hyperaldostero nism (IHA), which is due to bilateral hyperplasia of the adrenal corte x. We present two patients with bilateral APA in whom the diagnosis wa s made histochemically by analyzing steroidogenic enzymes. They showed hypokalemia, high plasma aldosterone concentration (PAC) and suppress ed plasma renin activity (PRA). Bilateral adrenal tumors mere represen ted by computed tomography, and surgical resection was performed. In b oth cases, cytochrome P-450 and other enzymes that were involved in al dosterone synthesis were found mainly in tumor, but little in the zona glomerulosa of the adjacent adrenals, which showed paradoxical hyperp lasia. Such cases are difficult to distinguish from IHA. The two disor ders mere differentiated by immunohistochemical analysis of steroidoge nic enzymes.