From 1967 to 1991 we have diagnosed and treated 73 adrenal tumors in 63 patients: 12 pheochromocytomas, 24 adrenal cortical adenomas, 15 hyperplasias, 16 carcinomas, 3 myelolipomas, 2 cysts and 1 neuroblastoma. We conducted a retrospective study to analyze the preoperative images obtained by different diagnostic techniques and attempted to correlate tumor size and site with the results of the histological analysis of the surgical specimen. Nephrotomography with pneumoretroperitoneum and IV Nephrotomography were useful in detecting the increase of the size of the gland in 10 of 25 cases submitted to these procedures (40%). Arteriography as second or third technique of choice confirmed the presence of an adrenal tumor in 15 of the 21 cases evaluated by this procedure (70%). US and CT detected 94% (31/33) and 100% (33/33) of the cases, respectively. Fourteen cases were incidentally discovered by CT (7) and US (7). A direct relationship between tumor size and degree of malignancy could be established since the carcinomas had a mean diameter of 7 cm (range 5 to 12 cm). Concerning the histologic nature of the disease, specific images were found in 3 cases of adrenal myelolipoma (hyperechoic on US and of low density similar to fat on CT) and 2 cysts (anechoic with posterior band evidenced on us and liquid on CT). Radioisotopes were also utilized for tumor localization and there was positive uptake of I-131-IMBG in 2 cases of adrenal pheochromocytoma; 1 extra-adrenal (left lateral aortic paraganglioma) and 1 case of malignant adrenal pheochromocytoma with metastasis to the lungs.(ABSTRACT TRUNCATED AT 250 WORDS)