INCIDENTALLY DISCOVERED ADRENAL-TUMORS - ENDOCRINE SCINTIGRAPHIC CORRELATES

Hormonal and morphological data were investigated in 202 consecutive p atients with adrenal incidentalomas (171 unilateral and 31 bilateral) in an attempt to assess subclinical hyperfunction or malignancy. In ad dition to the classical evaluation, scintiscan was carried out in a la rge number of these patients. In unilateral incidentalomas, 83% showed normal hormonal function, whereas 17% had biochemical signs of adrena l overactivity (hyperaldosteronism in 3, hypercortisolism in 17, medul lary hyperfunction in 9). [Se-75]methylnorcholesterol scintigraphy dep icted malignant, space-occupying lesions as decreased or absent radiot racer uptake by the mass, and cortical adenomas as increased or normal uptake. In cortical adenomas a relationship between radiocholesterol uptake and degree of functional autonomy was demonstrated. [I-123]Meta iodobenzilguanidine scintiscan visualized 7 of 8 pheochromocytomas. In bilateral incidentalomas, abnormal adrenal function was more frequent , accounting for 29% of cases (hyperaldcrsteronism in 3, hypercortisol ism in 3, adrenal insufficiency in 2, and congenital adrenal hyperplas ia in 1). Malignant lesions were not scintigraphically visualized. [Se -75]Methylnorcholesteral scan also provided functional information in the case of a cortisol-secreting adenoma and an aldosteronoma with a c oncomitant contralateral nonhypersecreting adenoma, showing the greate st uptake in the hyperfunctioning adenomas. In both unilateral and bil ateral lesions, endocrine testing failed to differentiate benign from malignant tumors. Although hormonal assessment is mandatory to clarify the functional patterns, only morphofunctional examination by scintis can seems to provide more data about the likelihood of malignancy.