Aldosterone-Producing Adenomas of Increased Size Are Associated With Higher Steroidogenic Activity

There are inconsistent results and insufficient evidence as to whether an association exists between the size and aldosterone-producing ability of aldosterone-producing adenomas.

We further investigated this possible association retrospectively.

A total of 142 cases of primary aldosteronism diagnosed as unilateral by adrenal venous sampling at 2 referral centers between 2009 and 2019 were included. We classified these individuals into small and large tumor groups using a diameter of 14 mm as a cutoff. This size was the median diameter of the tumor on the affected side of the adrenal gland. We compared plasma aldosterone concentration (PAC), plasma renin activity (PRA), PAC to PRA ratio, PAC from a saline infusion test (SIT), urinary aldosterone secretion (uAld), and serum potassium as indices of aldosterone-producing ability between the 2 groups. In some cases, we conducted histopathological evaluations and detection of the KCNJ5 mutation.

PAC, PAC to PRA ratio, PAC from SIT, and uAld were higher and serum potassium was lower in the large tumor group. PAC, PAC from SIT, uAld, and serum potassium significantly correlated with tumor diameter. PRA was not associated with tumor diameter. Clear cell-dominant cases were more common in the large tumor group, while cases showing a strong expression of CYP11B2 were not significantly different between the groups. KCNJ5 mutations tended to be more common in the large tumor group.

The higher aldosterone-producing ability in larger adenomas can be used to infer the responsible lesion and disease type.