Adrenal tumors diagnosed after work-up of an incidentaloma can be responsible for excessive secretion of steroids or catecholamines. On the other hand, an infiltrative process (metastases, infection...) involving both adrenals can cause adrenal insufficiency. Clinical and biological work-up is performed to detect hormonal imbalances requiring treatment, and further characterize the nature of the lesion. Screening for pheochromocytoma should be systematic with metanephrine assays on urine or plasma. Screening for cortisol secreting tumors, often responsible for Cushing's syndrome of moderate severity (pre-clinical) in patients with incidentaloma, will be performed using the overnight dexamethasone suppression test (1 mg). Depending on results from the imaging and clinical work-up, excessive secretion of aldosterone, androgens or steroid precursors may sometimes be investigated. In patients with bilateral incidentalomas, the normal synacthen test and ACTH assay are also performed to exclude adrenal insufficiency.