Prevalence of adrenal and extra-adrenal Conn syndrome in hypertensive patients

Background: Primary aldosteronism (PA) is caused by an adrenal aldosterone-producing tumor (A-APT) or adrenal hyperplasia. An extra-adrenal APT (E-APT) as a cause of PA has been reported in 5 cases. Autopsy studies show a high incidence of ectopic adrenocortical tissue. We did a prospective study of the prevalence of A-APTs and E-APTs and the biochemical features of E-APTs in patients with PA. Methods: Hypertensive patients (N=3900) referred to our unit were screened for PA by measuring renin activity, urinary aldosterone-18-glucuronide, tetrahydroaldoster-one, and 18-hydroxycorticosterone (18-OH-B). Primary aldosteronism was found in 257 cases. The differentiation between A-APTs and adrenal hyperplasia was based on the results of postural response of renin, plasma aldosterone, 18-OH-B, computed tomography, isotope scanning, or adrenal venous aldosterone. Ultrasound examination of the abdomen was used to screen for E-APT. Results: The cause of PA was bilateral adrenal hyperplasia in 101 cases, unilateral adrenal hyperplasia in 2, an A-APT in 146, and an E-APT in 1. The site of aldosterone production was uncertain in 7 patients who had normal adrenal glands on computed tomography but refused to undergo isotopic scanning and adrenal venous catheterization. Ultrasound examination disclosed normal retroperitoneum in 4 of the 7 cases but could not rule out E-APT in 3 cases. The biochemical features of the patient with the E-APT were similar to classic A-APT, with low renin, high aldosterone, and high 18-OH-B values without appropriate response to posture of to short-term volume expansion. The excision of the E-APT in the right kidney resulted in normalization of blood pressure and renin, aldosterone, and 18-OH-B levels. Conclusion: Although E-APT is rare,it should be considered in the interests of specific therapy for PA because aldosterone-secreting malignant ovarian tumors also have been reported.