ABSTRACT
112 A 15-year-old, spayed female Cocker Spaniel underwent abdominal ultrasonography (112a) to evaluate a mass that was detected on abdominal radiographs located in the area of the left kidney and adrenal gland. Ultrasonography revealed a large adrenal mass cranial to the left kidney closely associated with the aorta. A necropsy specimen of an adrenal mass (open arrows) invading the caudal vena cava (thrombus delineated by white arrows) in another patient is illustrated (112b). Both patients had exhibited signs of restlessness and weight loss, and were diagnosed with hypertension. i. What is the most likely kind of adrenal tumor in both these patients? ii. Aggregates of extra-adrenal chromaffin cells usually are located near sympathetic ganglia. When tumors of chromaffin cells occur in these extra-adrenal sites, what are they also known as? iii. Signs associated with adrenal medullary tumors are vague in animals and often go unnoticed, explaining why many of these tumors are diagnosed on postmortem examination. Clinical signs are due to the tumors’ ability to produce and secrete excess catecholamines. These signs can be persistent but are usually paroxysmal, complicating diagnosis. Other symptoms reported are related to the invasive nature of some of these tumors. What clinical signs or related conditions are associated with this tumor? iv. What pharmacological agents can be used to lessen the effects of excess catecholamine release in patients with pheochromocytomas in order to prepare them for surgery or for medical management of the symptoms?
