A case of unilateral adrenal hyperplasia: the diagnostic dilemma of hyperaldosteronism

Objective: To report the successful laparoscopic surgical management of a case of right unilateral adrenal hyperplasia. Methods: We present a case of unilateral adrenal hyperplasia and review the pertinent literature. The effectiveness of surgical treatment of unilateral adrenal hyperplasia is evaluated. Results: A 50-year-old man had a 7-year history of hypertension, which had been treated with antihypertensive medications. On initial assessment, he was taking long-acting diltiazem, 240 mg twice a day, and his blood pressure was 150/84 mm Hg. He was noted to have recurrent hypokalemia, low plasma renin activity, increased plasma aldosterone concentration, and high urinary aldosterone levels. Magnetic resonance imaging of the adrenal glands revealed a normal left adrenal gland and fullness of the right adrenal gland. Selective adrenal vein catheterization showed findings consistent with a right-sided adrenal gradient. Surgical removal of the right adrenal gland laparoscopically alleviated his symptoms and cured his hypertension and hypokalemia. Pathologic examination of the right adrenal gland revealed diffuse hyperplasia of the zona fasciculata and zona reticularis. Plasma aldosterone, renin, and potassium levels returned to normal postoperatively, and his blood pressure declined to 120/70 mm Hg. At 1-year follow-up, the patient remained normotensive without the need for antihypertensive agents. Conclusion: This rare type of hyperaldosteronism, known as unilateral adrenal hyperplasia, is difficult to categorize not only because it fails to typify a conventional subtype but also because it is difficult to confirm the pathologic diagnosis. Recognition of the variety of provocative, biochemical, and imaging results that may be seen in this disorder is important in making the correct diagnosis. Determining unilaterality of disease by selective adrenal vein sampling can result in a cure of hypertension and hypokalemia by surgical resection. (Endocr Pract. 2000;6:153-158)