Adrenal tumors larger than 6 cm are unusual but show a greater incidence of malignant etiologies than smaller adrenal tumors. The scarce information about adrenal macrotumors (AMT) induced us to study prospectively all patients who were seen in our clinic during the period 1984-1988 and were diagnosed by computed tomography (CT) to have an adrenal mass greater than or equal to 6 cm. The clinical characteristics, including the main complaint, tumoral secretory activity, CT findings and histologic diagnosis from 18 patients are described; they represented a 0.3% of the total amount of abdominal CT studies performed. Seventy-two % of AMT resulted to be non cortisol or catecholamines secreting masses, and from them, a 38% corresponded to malignant etiologies characterized by marked and rapid weight loss. Four out of five hormone secreting AMT corresponded to pheochromocytomas, while the fifth one resulted to be a bilateral macronodular hyperplasia secreting cortisol. In two cases AMT did not correspond to a genuine adrenal mass, resulting to be a malignant histocytoma in one case and a hydatidic cyst in other one. When performed in two occasions, a percutaneous needle biopsy was a valuable diagnostic tool, permitting to diagnose a lymphoma and a tuberculoma.
In conclusion: 1) AMT correspond mainly to non cortisol or catecholamines secreting tumors, often malignant; 2) not all AMT diagnosed by CT correspond to true adrenal masses; 3) percutaneous needle biopsy can be a helpful procedure for diagnosing nonfunctioning solid AMT.