What is the role of ultrasonography in the follow-up of adrenal incidentalomas?

OBJECTIVES: The incidental discovery of an adrenal mass has become a frequent finding because of the increased use and technical improvement of computed tomography (CT) and magnetic resonance imaging. The approach to the investigation of these masses is ill-defined, and unequivocal guidelines for their management are lacking. The first problem concerns the distinction between malignant masses requiring surgery and the more frequent benign masses. In the case of a benign mass, an additional problem is the method of follow-up, considering cost, discomfort to the patient, and the consequences of false-positive results. The aim of this study was to evaluate the possible role of ultrasonography (US) in the follow-up of incidentally discovered adrenal masses. METHODS: Two hundred eight cases of adrenal incidentalomas consecutively diagnosed in Piedmont, Italy from 1989 to 1996 and collected for a retrospective multicenter analysis were used. The US and CT characteristics of the adrenal masses were compared in patients who underwent surgery. RESULTS: Most patients were 50 to 69 years of age; women were predominantly affected. CT was more reliable than US in detecting the malignant nature of an adrenal lesion. The mass diameter measured by US and CT was clearly correlated. CONCLUSIONS: At diagnosis, US was not sufficiently reliable in evaluating adrenal mass characteristics. Considering the high correlation between US and CT size estimation, in the case of a presumably benign lesion, US could be considered a simple, economic, and effective method of follow-up, with CT limited to evaluating masses growing over time (CT remains mandatory at diagnosis).