US and CT evaluation of diffusely enlarged adrenal gland.

Normal adrenal gland contains an anteromodial ridge and two asymmetric wings. This results in the characteristic features of cross-sectional images in different levels of a section. When adrenal gland is diffusely enlarged, it initially becomes thickened. As it grows larger, it may stimulate a focal mass lesion or it may appear irregular in shape. However, the basic forms in different section planes are still somewhat maintained. In bilateral adrenal hyperplasia, the medulla may be seen as a highly echogenic linear structure on US and a high-density linear structure on CT. The other causes of diffuse adrenal enlargement are hemorrhage, infectious disease, infiltrating neoplastic disease, and congenital metabolic deficiency disease.