[Differential diagnostic problems in the echographic study of adrenal metastases]

The sonographic detection of adrenal masses in patients with neoplasms, especially neoplasms of the lung, can be related to the presence of both metastases and adenomas. In order to assess the benign/malignant nature of such lesions, the adrenal glands of 43 patients with neoplasms (36 of them lung cancers) were studied with sonography (US) and fine needle aspiration biopsy (FNAB): in all, 58 masses were seen (28 monolateral and 15 bilateral). Six lesions (13%) presented with cytological features of benignancy, and on US they appeared as hypoechoic (as compared to the liver), round masses, with regular margins, ranging in size from 1.2 cm to 3.4 cm (average: 2.6 cm). In the remaining 34 patients (80%), cellular material with features of malignancy was obtained with FNAB. The US appearance of these metastases was heterogeneous, with the same echogenicity as the liver, and average size greater than 3 cm. On the basis of our data, the limit of 3 cm (if we consider the average dimension), corresponds to the threshold of benignancy, as well as the monolateral and hypoechoic appearance of the lesion. To sum up, the use of FNAB should be limited to those lesions which present with typical adenomatous features and for borderline lesions, while the diagnosis of metastasis is sufficiently accurate (p less than 0.001) in case of bilateral or isoechoic lesions greater than 3 cm.