Adrenalectomy is performed to remove functional masses such as adrenocortical hyperplasia (Cushing's disease), cortisol-secreting adenoma or adenocarcinoma (Cushing's syndrome), aldosterone-secreting adenoma (Conn's syndrome), pheochromocytoma, and adrenal causes of feminizing or virilizing syndromes. Non-functional masses that are also treated with adrenalectomy include adrenal adenocarcinoma, symptomatic adrenal cysts or angiomyolipomas, adrenal incidentalomas > 4 cm discovered on imaging studies, and isolated adrenal metastases with a favorable tumor biology.

With functioning tumors confirmed biochemically, a CT or MRI is performed to determine the side location of the neoplasm as well as its size, local invasion, and hepatic metastases. Patients with a diagnosis of pheochromocytoma receive a 131I-MIBG scan to localize occult second tumors or metastatic disease to the liver, lung, or bone. Selective venous sampling from the adrenal veins and inferior vena cava is useful to confirm the diagnosis of an aldosterone-secreting adenoma versus bilateral adrenal adenomas or micronodular hyperplasia of the zona glomerulosa. When metastases are being evaluated and resection is under consideration, FDG–PET scan is a useful adjunct.