Ultrasound Case Report Block 16 By Urshulaa Dholakia

Pheochromocytoma Excessive catecholamine producing tumor of chromaffin cells of the adrenal gland Incidence uncommon in dogs, rare in cats Median age 11 yrs; generally > 7 yrs Antemortem diagnosis difficult – cannot aspirate or biopsy the mass and tests for humans not available or accurate for veterinary medicine Usually unilateral with the other adrenal appearing normal in size and shape. Other differentials, especially hyperadrenocorticism should be investigated Hyperadrenocorticism can be concurrent in 20% of animals with pheochromocytoma, and can cause complications during anesthesia because of hypercoagulability

Case Example Gypsy – Patient # yr old spayed Cocker Spaniel Presented on ER to NCSU after referring DVM’s radiographs showed significantly reduced abdominal and retroperitoneal detail History: One week duration of diarrhea and straining to defecate, with progression to vomiting and anorexia after starting oral antibiotics (metronidazole and amoxicillin). Two prior cystotomy surgeries for calcium phosphate stones, most recently 8/2006.

rDVM Radiographs

Abdominal ultrasound Retroperitoneal effusion

Adrenal mass!

CT scan 47 mm contrast enhancing left adrenal mass Deviation of colon and major vessels

Advantage of ultrasound Non-palpable organ Radiographs may not be diagnostic Generalized enlargement vs. nodular

Limitations of Ultrasound Non-specific enlargement Must perform invasive sample collection (cytology, biopsy) Other differentials must be considered: –Hyperadrenocorticism –Benign nodular hyperplasia

Outcome of Gypsy Hospitalized until surgery one week later Received phenoxybenzamine and propranolol PO BID to control “pheo” induced hypertension Surgery was successful – mass was resected from abdominal cavity, however was found to be adhering to the left kidney, caudal vena cava, and left renal artery – incomplete excision but patient survived Histopathology of mass confirmed pheo Patient is doing great – owners say she acts 5 years younger; not pursuing chemotherapy

Prognosis for Pheo’s Animals with pheochromocytomas are at high risk for sudden collapse, acute hemorrhage, death, and severe hypertension Perioperative mortality rate is about 50% Animals surviving surgery have 1-3+ years, depending on concurrent diseases Prognosis is still guarded