Unanticipated adrenal masses are frequently encountered in modern, high resolution diagnostic imaging. Most often, these masses are benign adrenal adenomas, but when detected they necessitate a clinical evaluation sufficient to exclude subclinical endocrine disease, primary adrenal cancer, and remote metastases to the adrenal glands from other malignancies. These "incidentally-discovered" adrenal masses or so-called "adrenal incidentalomas" can be further evaluated with CT, MRI, and nuclear medicine imaging techniques. A substantial literature supports the use of each of these modalities to non-invasively characterize these neoplasms that have been considered by some as a 'disease' of modern imaging technology.