An incidental adrenal mass is defined as a mass lesion found unexpectedly in an adrenal gland by an imaging procedure, most commonly, CT. The widespread use of CT for the investigation of abdominal pain, tumor staging, or the evaluation of sepsis has presented new challenges for the clinical endocrinologist. The clinician must decide what further steps must be taken to identify the cause of the newly discovered and unexpected adrenal mass and to recommend appropriate therapy. Few consultations in clinical endocrinology cover such a wide range of diagnostic possibilities, which can include entities such as adrenal infection, adrenal neoplasm, a tumor metastatic to the adrenal, an inherited adrenal enzymatic defect causing irregular adrenal gland enlargement or hemorrhage secondary to an unrecognized life-threatening coagulopathy. The clinical endocrinologist must decide what adrenal hormones might be either excessive or deficient and select the most cost-effective way of identifying these hormonal alterations.

This review article discusses the diagnostic possibilities that might result in an adrenal mass lesion and suggests the most appropriate diagnostic evaluation to verify the most likely cause. An algorithm is formulated for lesions that do not have a clinically apparent reason after initial evaluation, a situation that, unfortunately, occurs frequently.