Nonfunctional adrenal lesions without loss of signal intensity on MRI: Whose problem is it? The patient's? The surgeon's?

BackgroundCurrent indications for adrenalectomy include functional adrenal tumors and potentially malignant tumors based on imaging studies. We evaluated the effectiveness of magnetic resonance imaging (MRI) in obtaining a correct preoperative diagnosis.MethodFifty-three patients with nonfunctional adrenal lesions were analyzed. Indications for adrenalectomy of nonfunctional adrenal lesions included >6 cm in size and ≤6 cm in size with atypical characteristics on MRI. Lesions with a size of >6 cm, local invasion, irregular margins, and chemical-shift imaging that demonstrated no loss of signal intensity on out-of-phase images were considered suspected of malignancy.ResultsAdrenal lesions of >6 cm in size exhibited an 80-fold increased prediction of malignancy (OR: 80; 95% CI 7.8–813), whereas irregular margins and local invasion exhibited a 45-fold (OR: 45; 95% CI 6.4–312.5) and a 12-fold (OR: 12; 95% CI 4.6–30.6) increased occurrence of malignancy, respectively. The loss of signal intensity did not affect the prediction of malignancy.ConclusionThe rate of unnecessary tumor resections that are <6 cm in size can be decreased by performing adrenal biopsies in selected cases or by short-term follow-up to prevent the insufficiency of imaging techniques.