Adrenal Tumors

The majority of adrenocortical tumors are functional, with clinical signs reflecting the type of hormone being produced by the neoplasm. The differential diagnosis includes adrenocortical adenoma, adrenocortical adenocarcinoma, pheochromocytoma, aldosteronoma, and various combinations of coexisting disorders. The endocrinologic evaluation of an adrenocortical mass can be confusing because of the wide variations in test results that can occur. The most commonly used tests include the adrenocorticotropic hormone (ACTH) stimulation test, the low-dose dexamethasone suppression (LDDS) test, and the high-dose dexamethasone suppression (HDDS) test. Abdominal ultrasonography is a valuable aid for diagnosing adrenal gland tumors. The use of Computed tomography (CT) has greatly facilitated the detection of adrenal tumors. Macroscopic vascular invasion due to a tumor thrombus or a blood thrombus has been reported in approximately 25% of reviewed cases and may occur in 10-20% of canine adrenocortical tumors and 30-50% of dogs with pheochromocytomas.