Clinical experience of incidentally discovered adrenal tumor with particular reference to cortical function

We reviewed 14 male and 9 female patients with adrenal tumor discovered incidentally by imaging studies in an attempt to assess adrenal function, mainly cortical function. Pathological diagnosis consisted of cortical adenoma in 12 patients, cortical nodular hyperplasia in 2, medullary hyperplasia in 1, cavernous hemangioma in 1, metastatic tumor in 4 and cyst in 2. Another adrenal cyst was diagnosed by percutaneous puncture. In all patients peripheral levels of plasma cortisol and aldosterone were normal. Plasma catecholamine levels were also normal except for 1 patient with medullary hyperplasia who had equivocal elevation. Among the patients with cortical adenoma and hyperplasia, however, 5 of 10 (50%) had excessive excretion of 24-hour urinary 17-hydroxycorticosteroids, 4 of 13 (31%) had a loss of plasma cortisol circadian rhythm and 7 of 14 (50%) had insufficient suppression on the dexamethasone test. Furthermore all patients had an increased ipsilateral uptake that was not suppressed after dexamethasone on 131iodine-adosterol scintigraphy, while a diminished contralateral uptake was noted in 5 of 15 (33%). Postoperatively, hypertension decreased to normal in 2 of 3 patients and impaired glucose tolerance was improved in 1 of 2. Two patients with cortical adenoma who exhibited a loss of plasma cortisol circadian rhythm experienced postoperative adrenal insufficiency. These data indicate that a considerable number of incidentally discovered adrenal tumors are not nonfunctioning particularly in reference to glucocorticoid secretion, and adrenalectomy seems to be beneficial in some of those patients with hypertension or impaired glucose tolerance.