Differential diagnosis of solid adrenal masses using adrenocortical scintigraphy

To evaluate the diagnostic contribution of adrenal scintigraphy with 75-Se-selenomethylcholesterol in adrenal masses, 42 patients have been studied. All of them had a solid adrenal mass discovered on computed tomography (seven bilateral). None of the patients showed any symptoms or clinical signs that might indicate the existence of adrenal dysfunction. Twenty-nine of them had known extra-adrenal primary malignant disease. Forty-nine adrenal tumours were detected with an average size of 3.29 cm (range 1.5-12 cm). Eighteen lesions showed increased uptake of radiocholesterol on the side of the adrenal mass, all of which were either proven to be benign, or behaved in a benign fashion. Twelve lesions showed normal uptake (10 in the benign group and one lung carcinoma metastasis), all but one (2.5 cm) being smaller than 2 cm. Decreased uptake was observed in 20 lesions (15 metastases, two nonfunctional adrenal carcinomas, one myelolipoma and two tuberculous infectious lesions). Adrenocortical scintigraphy provides functional information about adrenal masses and is useful in differentiating between benign and malignant lesions.