Case Report: PDF OnlyPrimary Aldosteronism Caused by Unilateral Adrenal Hyperplasia: Rethinking the Accuracy of Imaging StudiesChen, Su-Yua; Shen, Sjen-Jungb; Chou, Chien-Wena, *; Yang, Chwen-Yia; Cheng, Hon-Meia Author Information aDivision of Endocrinology and Metabolism, Department of Medicine, Chi-Mei Medical Center, Taiwan, R.O.C. bDivision of Endocrinology and Metabolism, Department of Medicine, Chi-Mei Hospital, Liouying, Taiwan, R.O.C. *Correspondence to: Dr. Chien-Wen Chou, Division of Endocrinology and Metabolism, Department of Medicine, Chi-Mei Medical Center, 901, Chung Hwa Road, Yung Kang City, Tainan 710, Taiwan, R.O.C. E-mail: [email protected] Received: April 12, 2005; • Accepted: November 16, 2005. Journal of the Chinese Medical Association: March 2006 - Volume 69 - Issue 3 - p 125-129 doi: 10.1016/S1726-4901(09)70190-X Metrics Abstract A rare type of aldosteronism, known as unilateral adrenal hyperplasia (UAH), is difficult to diagnose, not only because it fails to conform to the typical common subtypes, but also because imaging results are unreliable. We report 2 Taiwanese patients with UAH. Case 1 was a 44-year-old man with 2 episodes of hypokalemic paralysis. Hypertension and suppressed plasma renin activity (PRA) with elevated plasma aldosterone concentration (PAC) were observed. Abdominal computed tomography (CT) and magnetic resonance imaging (MRI) showed a right adrenal mass, but adrenal scintigraphy revealed no definite laterality. The patient underwent a laparoscopic right adrenalectomy. Adrenal cortical hyperplasia was discovered from results of the histologic analysis. Case 2 was a 33-year-old woman referred for hypokalemia, hypertension, and a left adrenal mass found on a CT scan. However, MRI revealed normal adrenal glands. The adrenal vein sampling for PAC showed overproduction of PAC from the left adrenal gland. A laparoscopic left adrenalectomy was done. Pathology results revealed micronodular cortical hyperplasia with central hemorrhage. Blood pressure, plasma potassium, aldosterone, and renin activity levels returned to normal after operation in both cases. Both patients have been well for 3 years and 16 months, respectively, after surgery. We review the literature and discuss the limitations of imaging studies. © 2006 by Lippincott Williams & Wilkins, Inc.