The indications for adrenalectomy are numerous but the two most common are for a Functioning Endocrine Tumor and the suspicion of a malignancy. "Functioning tumors" refer to tumors that secrete a substance that acts on the body to produce an untoward effect. The most common in the adrean gland are pheochromocytoma, aldosteronoma and cortisol secreting tumor that results in Cushing's syndrome.
Each of these will be discussed separately. Suspicion for malignancy includes tumors picked up on other tests by accident, or incidentally. Not surprisingly they are referred to as incidentalomas. Other cancers can spread to the adrenal gland and in some cases there are benefits to survival by removing them.