Evaluation and Management of the Incidental Adrenal Mass

Abstract

A s the use of imaging studies in medicine increases, so does the discovery of unexpected pathologic findings. One of the more common unexpected findings revealed by computed tomography (CT), magnetic resonance imaging (MRI), or ultrasonography is an adrenal mass, called an inciden-tal adrenal mass, or incidentaloma (Figure 1). The incidence of adrenal masses found on abdominal CT scans is between 0.6% and 1.3%. The incidence of these masses on all CT scans, including thoracic, abdominal, and pelvic, is between 0.4% and 4.4%. The indication for the CT scan varies (Table). In contrast, the incidence of adrenal masses at autopsy in patients who had no evidence of adrenal disease is between 1.4% and 9%. It is difficult to answer a patient's questions when a mass is found. This article attempts to simplify the workup and direct the evaluation of the mass. It begins by discussing the differen-tial diagnosis and imaging studies that can be used and then comments on several hyperfunctioning and malignant adrenal masses. DIFFERENTIAL DIAGNOSIS The differential diagnosis of the adrenal mass comprises a long list: adenoma, myelolipoma, cyst, lipoma, pheochromocy-toma, adrenal cancer, metastatic cancer, hyperplasia, and tuber-culosis (3). More than half of incidentalomas are benign or