Adrenal incidentaloma: does an adequate workup rule out surprises?

Adrenal incidentaloma remains a diagnostic challenge. Despite well-established management guidelines, the long-term results of following these guidelines are unknown. We sought to determine how accurately these guidelines identify functioning incidentalomas and how often these guidelines result in adrenalectomy for benign tumors.

We catalogued adrenal incidentalomas from a retrospective review of 500 consecutive adrenalectomies at a single institution. The outcome measures studied were patient demographics, preoperative biochemical analysis, imaging characteristics, tumor size, type of operation performed, and postoperative histologic diagnosis.

Eighty-one of the 500 adrenalectomies performed were for incidentalomas. Size was the only significant characteristic that distinguished cortical cancers from benign adenomas. Only 1 out of 26 functioning tumors was incorrectly identified on preoperative workup. We also found that 25% of cortisol-secreting incidentalomas were cystic, and that benign adenomas accounted for 42% of all tumors resected.

Current guidelines accurately predict the functional status of adrenal incidentalomas. Some cystic lesions may be functioning and should therefore be screened for hormonal hypersecretion. However, even with the most up-to-date diagnostic tools available, most adrenal incidentalomas resected are benign tumors.