Imaging of Adrenal Incidentalomas: Current Status
N. Reed Dunnick and Melvyn Korobkin

1 Department of Radiology, University of Michigan Health System, 1500 E. Medical Center Dr., Ann Arbor, MI 48109-0030. Received January 11, 2002; accepted after revision February 26, 2002.

Since the early 1980s, incidentally discovered adrenal masses have become a common clinical problem as a result of the more widespread use of high-resolution anatomic imaging procedures, especially CT and MR imaging. In patients without a known extraadrenal primary malignancy, most of these lesions are benign nonhyperfunctioning adenomas. Even in patients with a primary neoplasm in whom an adrenal metastasis is an important consideration, most adrenal masses are also benign. However, despite the high frequency of a benign lesion, especially adrenal cortical adenoma, as the cause of an incidentally detected adrenal mass, it is important to distinguish the benign lesions from the less common malignant masses, which require intervention, to establish the correct diagnosis.

An adrenal mass detected during a CT or MR imaging examination that is being performed for reasons other than suspected adrenal abnormalities is often referred to as an adrenal incidentaloma. The continuing uncertainty about the appropriate clinical and imaging management of adrenal incidentalomas was attested to by the National Institutes of Health consensus conference on this subject on February 4-6, 2002. The purpose of this article is to review the imaging features of nonhyperfunctioning adrenal masses and the recent advances in noninvasive imaging methods to help differentiate benign from malignant lesions. The changing role for percutaneous biopsy of an adrenal mass will also be addressed.