Cushing disease and unilateral primary aldosteronism confounded by a nonfunctioning contralateral adrenal incidentaloma.

The discovery of an adrenal incidentaloma should prompt an evaluation for the presence of malignancy and autonomous hormonal secretion. Concomitant adrenal nodule and hypercortisolism or primary aldosteronism does not inherently confirm the adrenal lesion as the source of excessive hormone. Localization studies are needed to ensure proper identification of the source of hormone oversecretion prior to consideration of surgical resection. We report a case in which a patient presented with an adrenal incidentaloma but was found through extensive hormonal testing and localization studies to have Cushing disease and primary aldosteronism, which was localized to the contralateral adrenal gland, whereas the adrenal incidentaloma that prompted the initial evaluation appeared to be nonfunctioning. Our case report highlights the importance of localizing the functioning lesion in the context of an adrenal incidentaloma.