This report presents the clinical, laboratory, imaging, and pathologic findings in 61 dogs with pheochromocytoma by retrospective evaluation of medical records. Pheochromocytomas were diagnosed by histopathologic examination of tissue specimens in all dogs. Special stains (chromogranin A and synaptophysin) also were used t o confirm the chromaffin cell origin of the tumors. Epidemiologic findings were in agreement with previous studies, indicating that pheochromocytomas affect middle-aged t o older dogs with no apparent gender or breed predilection. The tumor was considered clinical in 21 dogs (34%), was responsible for abnormalities related t o a space-occupying mass in 7 dogs (ll%), and was an incidental finding in 35 dogs (57%). The hematologic and biochemical findings were nonspecific. Hypertension was detected in 10 of 23 (43%) dogs tested, but all hypertensive dogs had concurrent diseases that may have heochromocytoma is a tumor of the chromaffin cells of P the adrenal medulla or sympathetic paraganglia'.2 that has been described in human beings, horses, cattle, dogs, cats, and laboratory rats.' Clinical diagnosis of pheochromocytoma is relatively rare.'.' A variety of vague and nonspecific clinical signs attributed to excessive secretion of catecholamines has been reported in dogs with pheochromo~y t o m a .~-* The mass effect or local invasion of structures by these tumors also can produce clinical signs. Approximately 50% of pheochromocytomas are discovered incidentally in dogs with no clinical signs or other problem caused by the tum0r.j Antemortem diagnosis of pheochromocytoma is difficult because of lack of specific clinical signs.' There are few comprehensive studies pertaining to pheochromocytomas in the veterinary literature and a paucity of information documenting the imaging diagnosis of this tumor.'.' The purpose of this study was to characterize the clinical, laboratory, imaging, and pathologic findings of pheochromocytoma in 61 dogs. findings, clinicopathologic data, imaging results, pathologic findings, and outcome for each dog. Signalment (breed and gender) of the 61 dogs was compared to that of the hospital population during the same period using chi square analysis. Hypotheses tested were accepted when P < .OS. Materials and MethodsMedical records were analyzed to determine if the tumor was clinical (group I), was responsible for abnormalities related to a space-occupying mass (group 2), or was an incidental finding (group 3). Criteria for including dogs in group 1 were selected from previous retrospective studies on pheochromocytoma'.' and included the presence of at least one of the following: weakness, lethargy; polyuria and polydipsia (PUPD); collapse, panting, dyspnea or tachypnea; vomiting, anorexia or inappetence; weight loss; seizures; tachyarrhythmias; pale mucous membranes; injected mucous membranes; fever; and cardiac arrest. Criteria for including dogs in group 2 were the presence of at least one of the following: ascites, limb edema, abdominal pain, abdominal distention, and ...

Caval thrombi associated with adrenal gland tumors are amenable to adrenalectomy and thrombectomy without significantly increased perioperative morbidity and mortality rates, assuming the surgeon is experienced in appropriate techniques.

Background: Some studies in dogs undergoing adrenalectomy for pheochromocytoma suggest that anesthetic complications and perioperative mortality are common. In humans, surgical outcome has improved with the use of phenoxybenzamine (PBZ) before adrenalectomy.Hypothesis: Dogs treated with PBZ before adrenalectomy have increased survival compared with untreated dogs. Animals: Forty-eight dogs that underwent adrenalectomy for pheochromocytoma. Methods: A retrospective medical record review for dogs that underwent adrenalectomy for pheochromocytoma at a veterinary medical teaching hospital over the period from January 1986 through December 2005.Results: Twenty-three of 48 dogs were pretreated with PBZ (median dosage: 0.6 mg/kg PO q12h) for a median duration of 20 days before adrenalectomy. Duration of anesthesia and surgery, percentage of dogs with pheochromocytoma involving the right versus left adrenal gland, size of tumor, and presence of vascular invasion were similar for PBZ-treated and untreated dogs. Thirty-three (69%) of 48 dogs survived adrenalectomy in the perioperative period. PBZ-treated dogs had a significantly (P 5 .014) decreased mortality rate compared with untreated dogs (13 versus 48%, respectively). Additional significant prognostic factors for improved survival included younger age (P 5 .028), lack of intraoperative arrhythmias (P 5 .0075), and decreased surgical time (P 5 .0089).Conclusions and Clinical Importance: Results from this retrospective study support treatment with PBZ before surgical removal of pheochromocytoma in dogs.

This retrospective study identifies parameters that might separate dogs with hyperadrenocorticism caused by adrenocortical tumors from dogs with pituitary-dependent hyperadrenocorticism. Further, an attempt was made to identify factors that could separate dogs with adrenocortical adenomas from dogs with carcinomas. The records of 41 dogs with hyperadrenocorticism caused by adrenocortical neoplasia were reviewed. The history, physical examination, urinalysis, hemogram (CBC), chemistry profile adrenocorticotrophic hormone (ACTH) stimulation and low dose dexamethasone test results were typical of the nonspecific diagnosis of hyperadrenocorticism. The preceding information on the 41 dogs with adrenocortical tumors was compared with that from 44 previously diagnosed pituitary-dependent hyperadrenocorticoid dogs. There was no parameter which aided in separating these two groups of dogs.Thirty dogs with adrenocortical tumors were tested with a high-dose dexamethasone test and none had suppressed plasma cortisol concentrations 8 hours after IV administration of 0.1 mg/kg of dexamethasone. In 29 of the 41 adrenal tumor dogs, plasma endogenous ACTH was not detectable on a t least one measurement (<20 pg/ml). The remaining 12 dogs from this group had nondiagnostic concentrations (20-45 pg/ml). Thirteen of 22 dogs (59%) with adrenocortical carcinomas had adrenal masses identified on abdominal radiographs and seven of 13 dogs (54%) with adrenocortical adenomas had radiographically visible adrenal masses. Thirteen of 17 adrenocortical carcinomas (76%) and five of eight adenomas (62%) were identified with ultrasonography. Radiographs of the thorax and ultrasonography of the abdomen identified most of the dogs (8 of 11) with metastatic lesions.In conclusion, the most sensitive tests in distinguishing dogs with pituitary-dependent hyperadrenocorticism from dogs with adrenocortical tumors were the plasma endogenous ACTH concentrations, abdominal radiography, and abdominal ultrasonography. None of these three tests alone, however, were completely reliable, suggesting the potential need for review of several tests when attempting to separate dogs with pituitary-dependent hyperadrenocorticism from those with adrenocortical tumors. Recognition of metastatic lesions with radiography and/or ultrasonography was the only parameter that separated dogs with adenomas from dogs with carcinomas. (Journal of Veterinary Internal Medicine 1991; 5:3-10)

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Results suggest that urolithiasis and urinary tract infection may be associated with hypercalcemia in dogs-with primary hyperparathyroidism, but that development of renal insufficiency is uncommon.

Irradiation is effective for local control of thyroid tumors, despite their slow regression rate. Results provided evidence that local tumor control affects metastatic outcome in dogs with thyroid carcinomas and is a strong basis for the development of new approaches that include irradiation in the management of dogs with advanced thyroid carcinomas. Improvements in local tumor control alone may be insufficient to improve survival times because of the high risk of metastatic spread before an initial diagnosis is made, which warrants initiation of early systemic treatment.

The medical records of 110 dogs treated for primary hyperparathyroidism were reviewed. Dogs were treated via parathyroidectomy (n=47), percutaneous ultrasound-guided ethanol ablation (n=15), or percutaneous ultrasound-guided heat ablation (n=48). Forty-five of 48 (94%) parathyroidectomies resulted in control of hypercalcemia for a median of 561 days. Thirteen of 18 (72%) ethanol ablation procedures resulted in control of hypercalcemia for a median of 540 days. Forty-four of 49 (90%) heat-ablation treatments resulted in control of hypercalcemia for a median of 581 days.