Adrenocortical carcinoma manifesting pure primary aldosteronism: a case report and analysis of steroidogenic enzymes.

Adrenocortical carcinoma manifesting pure hyperaldosteronism is extremely rare. We report here a 61-year-old woman with biochemically proven primary aldosteronism due to right adrenocortical carcinoma. Computed tomographic scan showed 4.5x5.3 cm lobulated mass with tiny calcification, while there was no significant uptake of 131I-iodomethyl norcholesterol in the tumor. Immunohistochemical analysis demonstrated expression of steroidogenic enzymes in the tumor tissue: P-450scc, P-45c21, 3beta-hydroxysteroid dehydrogenase, P450(17alpha), and P-450(11beta). In addition, we could demonstrate mRNA expression of aldosterone synthase (P-450aldo:CYP11B2) in the tumor by specific ribonuclease protection assay. This is the first report of a case of primary aldosteronism due to adrenocortical carcinoma, in which expression of all sets of steroidogenic enzymes required for aldosterone synthesis was proven.