ADRENAL ULTRASONOGRAPHY IN THE DOG

Case report: Successful medical management of adrenocortical carcinoma with metastasis in a Maltese dog

Introduction

Adrenocortical carcinoma (ACC) with metastasis has a grave prognosis, and adrenalectomy is associated with a high perioperative mortality rate in dogs. A favorable outcome following trilostane treatment in patients with metastatic ACC confirmed by a decreased size of the adrenal tumor and metastatic lesions has not been reported in dogs.

Case description

A 12-year-old neutered male Maltese dog was diagnosed with a right adrenal tumor and a hepatic mass. Adrenal-dependent hyperadrenocorticism (ADH) was diagnosed based on clinical signs and an adrenocorticotropic hormone stimulation test (ACTHST). In addition, tests for plasma metanephrine and normetanephrine ruled out a pheochromocytoma. Based on cytology and computed tomography, unresectable metastatic ACC was confirmed. The dog was managed with trilostane due to the presence of distant metastasis. Medical management improved the clinical signs and post-ACTHST cortisol concentrations. One year after the first presentation, the clinical signs and ACTHST test showed a favorable outcome. In addition, computed tomography revealed a decreased size of the right adrenal tumor and resolution of the hepatic mass.

Conclusions

Trilostane could be considered as a treatment option for unresectable metastatic ACC. A decrease in tumor size following treatment with trilostane has not been reported in dogs. This case report is the first to demonstrate a favorable outcome of metastatic ACC following trilostane mono therapy for >1 year.

Laboratory assessment of trilostane treatment in dogs with pituitary-dependent hyperadrenocorticism

Background

Results of ACTH stimulation test (ACTHst), pre‐ and post‐trilostane serum cortisol concentrations (SCCs), urine concentration (urine‐specific gravity [USG]), and urine cortisol : creatinine ratios (UCCRs) are common variables used to monitor trilostane treatment of dogs with pituitary‐dependent hyperadrenocorticism (PDH). However, none has consistently discriminated dogs receiving an adequate dose (A) from those overdosed (O) or underdosed (U).

Objectives

To assess and compare recommended monitoring variables, including serial SCCs in a cohort of dogs with PDH treated with trilostane.

Animals

Privately owned dogs with PDH (n = 22) and 3 healthy dogs (controls).

Methods

Prospective, multicenter, 2‐day study. On day “a” (randomized): ACTHst was completed. Day “b” (>2 to <7 days later): SCCs were assessed −0.5 hours, immediately before, and 1, 2, 2.5, 3, 3.5, 4, 6, 8, and 12 hours after trilostane administration. On the first study day, urine collected at home was assessed for USG, UCCR and owner opinions regarding PDH were categorized as: A (clinical signs resolved), U (remains symptomatic), or ill (possible O).

Results

At 27 pairs of evaluations, 7 dogs were categorized as A, 19 U, and 1 possible O (excluded from the study). There was overlap in SCC results from the A and U dogs at every time point. Results of USG, UCCR, and ACTHst did not discriminate A from U dogs. Trilostane suppresses SCC within 1 hour of administration and its duration of action in most PDH dogs is <8 hours.

Conclusions and Clinical Importance

No single variable or group of variables reliably discriminated A dogs from U dogs during trilostane treatment for PDH.

Outcome in dogs undergoing adrenalectomy for small adrenal gland tumours without vascular invasion

Veterinary studies have reported the outcome of adrenalectomies in dogs; however, these studies typically include a wide variety of adrenal tumour sizes, including cases with or without vascular invasion. The purpose of this study was to report outcome in a cohort of dogs with histologically confirmed small adrenal tumours without vascular invasion treated with adrenalectomy. This retrospective study was conducted using data from the University of Florida and University of California-Davis databases between 2010 and 2017. Dogs were included if they underwent excision of an adrenal gland tumour with a maximal diameter ≤ 3 cm, without evidence of vascular invasion to any location as assessed via computed tomography. Fifty-one dogs met the inclusion criteria. The short-term survival rate of dogs undergoing adrenalectomy was 92.2%, and one-year disease-specific survival was 83.3%. Twenty-eight of 51 (54.9%) dogs were diagnosed with a malignancy. Minor complications were observed commonly intra-operatively and post-operatively. Major complications were observed in six dogs, and included sudden death, respiratory arrest, acute kidney injury, haemorrhage, hypotension and aspiration pneumonia. Short-term mortality occurred in four dogs. Sudden death and haemorrhage were the most common major complications leading to death. While adrenalectomy is sometimes controversial because of the high perioperative mortality rates previously reported, the results of this study support that adrenalectomy for small tumours with no vascular invasion can be performed with low risk.

Diagnosis of spontaneous hyperadrenocorticism in dogs. Part 2: Adrenal function testing and differentiating tests

Hyperadrenocorticism is a relatively common endocrine disorder in dogs that has been extensively described. However, its diagnosis remains challenging because there is no true reference standard test, and a myriad factors can affect the diagnostic performance of the commonly used adrenal function tests. Ultimately, the diagnosis is based on a combination of signalment, history and clinical findings, and a variety of diagnostic test results. The second part of this review aims to appraise available data on diagnostic performance of adrenal function tests in naturally occurring canine hyperadrenocorticism.

Ultrasonographic features of adrenal gland lesions in dogs can aid in diagnosis

BACKGROUND

Ultrasonography to visualize adrenal gland lesions and evaluate incidentally discovered adrenal masses in dogs has become more reliable with advances in imaging techniques. However, correlations between sonographic and histopathological changes have been elusive. The goal of our study was to investigate which ultrasound features of adrenal gland abnormalities could aid in discriminating between benign and malignant lesions. To this end, we compared diagnosis based on ultrasound appearance and histological findings and evaluated ultrasound criteria for predicting malignancy.

RESULTS

Clinical records of 119 dogs that had undergone ultrasound adrenal gland and histological examination were reviewed. Of these, 50 dogs had normal adrenal glands whereas 69 showed pathological ones. Lesions based on histology were classified as cortical adrenal hyperplasia (n = 67), adenocarcinoma (n = 17), pheochromocytoma (n = 10), metastases (n = 7), adrenal adenoma (n = 4), and adrenalitis (n = 4). Ultrasonographic examination showed high specificity (100%) but low sensitivity (63.7%) for identifying the adrenal lesions, which improved with increasing lesion size. Analysis of ultrasonographic predictive parameters showed a significant association between lesion size and malignant tumors. All adrenal gland lesions >20 mm in diameter were histologically confirmed as malignant neoplasms (pheochromocytoma and adenocarcinoma). Vascular invasion was a specific but not sensitive predictor of malignancy. As nodular shape was associated with benign lesions and irregular enlargement with malignant ones, this parameter could be used as diagnostic tool. Bilaterality of adrenal lesions was a useful ultrasonographic criterion for predicting benign lesions, as cortical hyperplasia.

CONCLUSIONS

Abnormal appearance of structural features on ultrasound images (e.g., adrenal gland lesion size, shape, laterality, and echotexture) may aid in diagnosis, but these features alone were not pathognomic. Lesion size was the most direct ultrasound predictive criterion. Large and irregular masses seemed to be better predictors of malignant neoplasia and lesions <20 mm in diameter and nodular in shape were often identified as cortical hyperplastic nodules or adenomas.

Ultrasound Examination of the Feline Adrenal Gland

In vivo ultrasound measurements of the adrenal glands of a group of cats were compared with the physical measurements of the extirpated glands. The in vivo ultrasound measurements of length and thickness compared well with the physical measurements, but the width measure ments did not. Difficulty in probe placement was responsible for the lack of correlation. Sonographic assessment of the feline adrenal is shown to be feasible, and the normal physical parameters of the feline adrenal are presented.

Clinical findings in dogs with incidental adrenal gland lesions determined by ultrasonography: 151 cases (2007-2010)

OBJECTIVE

To determine the prevalence of and clinical features associated with incidental adrenal gland lesions (IAGLs) discovered during abdominal ultrasonography in dogs.

DESIGN

Retrospective case series.

ANIMALS

151 dogs with an IAGL and 400 control dogs.

PROCEDURES

Reports of ultrasonographic examinations of the abdomen of dogs performed during a 3.5-year period were reviewed. Adrenal glands were classified as having an IAGL if a nodule or mass was described or the width of either gland was ≥ 10 mm. For dogs with an IAGL, information regarding signalment, concurrent disorders, and outcome was obtained from the medical record. Findings were compared with those in a control population of 400 dogs examined during the same period.

RESULTS

An IAGL was detected in 151 of 3,748 (4%) dogs. Dogs with an IAGL were significantly older (median age, 11.25 years) and heavier (median body weight, 21 kg [46.2 lb]) than the control population (median age, 9.5 years; median body weight, 14 kg [30.8 lb]). Malignant tumors were reported in 6 of 20 (30%) dogs that underwent adrenal glandectomy or necropsy and had a maximum IAGL dimension that ranged from 20 to 46 mm; benign lesions all had a maximum dimension < 20 mm. Various coincidental conditions were reported in dogs with an IAGL, including nonadrenal gland malignant neoplasia in 43 (28.5%) dogs.

CONCLUSIONS AND CLINICAL RELEVANCE

IAGLs were more likely in dogs ≥ 9 years of age. On the basis of this small data set, malignancy should be suspected for IAGLs ≥ 20 mm in maximum dimension.

Use of computed tomography adrenal gland measurement for differentiating ACTH dependence from ACTH independence in 64 dogs with hyperadenocorticism

BACKGROUND

The measurement of adrenal gland size on computed tomography (CT) scan has been proposed for the etiological diagnosis of hyperadrenocorticism (HAC) in dogs. Symmetric adrenal glands are considered to provide evidence for ACTH-dependent hyperadrenocorticism (ADHAC), whereas asymmetry suggests ACTH-independent hyperadrenocorticism (AIHAC). However, there are currently no validated criteria for such differentiation.

OBJECTIVE

The aim of this retrospective study was to compare various adrenal CT scan measurements and the derived ratios in ADHAC and AIHAC cases, and to validate criteria for distinguishing between these conditions in a large cohort of dogs.

ANIMALS

Sixty-four dogs with HAC (46 ADHAC, 18 AIHAC).

METHODS

Dogs with confirmed HAC and unequivocal characterization of its origin were included. Linear measurements of adrenal glands were made on both cross-sectional and reformatted images.

RESULTS

An overlap was systematically observed between the AIHAC and ADHAC groups for all measurements tested. Overlaps also were observed for ratios tested. For the maximum adrenal diameter ratio derived from reformatted images (rADR), only 1/18 AIHAC dogs had a rADR within the range for ADHAC. For a threshold of 2.08, the 95% confidence intervals for estimated sensitivity and specificity extended from 0.815 to 1.000 and from 0.885 to 0.999, respectively, for AIHAC diagnosis.

CONCLUSION AND CLINICAL IMPORTANCE

Measurements from cross-sectional or reformatted CT scans are of little use for determining the origin of HAC. However, rADR appears to distinguish accurately between ADHAC and AIHAC, with a rADR > 2.08 highly suggestive of AIHAC.

The Clinical Utility of the Right Lateral Intercostal Ultrasound Scan Technique in Dogs

When performing abdominal ultrasonography in dogs, the right aspect of the liver, porta hepatis, right kidney, right adrenal gland, pancreas, and duodenum are often not fully visible from a ventral, or subcostal, approach. The right lateral intercostal plane is an alternative approach that allows evaluation of these structures. This report provides multiple case examples that demonstrate the sonographic anatomy via the right intercostal approach. Other cases are included to demonstrate indications for this approach. Animals in which the right intercostal approach may prove most useful include large- and giant-breed dogs; deep-chested dogs; dogs with gas distention of the stomach, duodenum, and colon; dogs with microhepatia; and those with abdominal effusion and pain.

Hyperadrenocorticism associated with sex steroid excess

Diagnosis of sex steroid excess or hyperadrenocorticism in dogs may be challenging. Unlike Cushing's disease, sex steroid excess may have a multitude of manifestations that differ from standard hyperadrenocorticism. In particular, the clinical scenario of a dog with sex steroid imbalance involves one of three systems: dermatologic, reproductive, or hepatic. The history of a dog with hyperadrenocorticism manifesting as sex steroid imbalance often lacks the classical clinical signs of polydipsia and polyuria. Dogs with sex steroid imbalance will often be of specific breeds such as miniature poodles and exhibit trunkal hair loss as the only sign. There is often involvement of the reproductive system, manifested as the growth of perianal adenomas in neutered male or female dogs. The most common laboratory findings consist of elevations in serum alkaline phosphatase and serum alanine transferase. The following article reviews the etiology, common signalment, clinical signs, and laboratory findings associated with atypical hyperadrenocorticism caused by sex steroid imbalance and then explores the medical, surgical, and radiation treatment options.

Evaluation of serum 17-hydroxyprogesterone concentration after administration of ACTH in dogs with hyperadrenocorticism

OBJECTIVE

To evaluate serum 17-hydroxyprogesterone (17-OHP) concentration measurement after administration of ACTH for use in the diagnosis of hyperadrenocorticism in dogs.

DESIGN

Prospective study.

ANIMALS

110 dogs.

PROCEDURE

Serum 17-OHP concentrations were measured before and after ACTH stimulation in 53 healthy dogs to establish reference values for this study. Affected dogs had pituitary-dependent (n = 40) or adrenal tumor-associated (12) hyperadrenocorticism or potentially had atypical hyperadrenocorticism (5; diagnosis confirmed in 1 dog). In affected dogs, frequency interval and borderline and abnormal serum 17-OHP concentrations after ACTH stimulation were determined. Serum cortisol concentrations were assessed via low-dose dexamethasone suppression and ACTH stimulation tests.

RESULTS

In healthy dogs, serum 17-OHP concentration frequency intervals were grouped by sex and reproductive status (defined as < 95th percentile). Frequency intervals of serum 17-OHP concentrations after ACTH stimulation were < 77, < 2.0, < 3.2, and < 3.4 ng/mL (< 23.3, < 6.1, < 9.7, and < 10.3 nmol/L) for sexually intact and neutered females and sexually intact and neutered males, respectively. In 53 dogs with confirmed hyperadrenocorticism, serum cortisol concentrations after ACTH stimulation and 8 hours after administration of dexamethasone and serum 17-OHP concentrations after ACTH stimulation were considered borderline or abnormal in 79%, 93%, and 69% of dogs, respectively. Two of 5 dogs considered to have atypical hyperadrenocorticism had abnormal serum 17-OHP concentrations after ACTH stimulation.

CONCLUSIONS AND CLINICAL RELEVANCE

Serum 17-OHP concentration measurement after ACTH stimulation may be useful in the diagnosis of hyperadrenocorticism in dogs when other test results are equivocal.

Diagnosis of canine hyperadrenocorticism

Canine hyperadrenocorticism is one of the most common endocrinopathies in dogs. Diagnosis remains difficult in some cases due to factors such as the presence of non-adrenal illness and limitations in the tests. Differentiation between the pituitary and adrenal forms is important for providing accurate prognostic information and delineating treatment options and protocols. This article reviews the tests available for diagnosis (screening) and differentiation and evaluates their advantages and disadvantages. Recommendations for testing are made.

Use of endogenous ACTH concentration and adrenal ultrasonography to distinguish the cause of canine hyperadrenocorticism

Twenty-nine dogs were diagnosed with hyperadrenocorticism (HAC). A single determination of endogenous plasma adrenocorticotropic hormone (ACTH) and adrenal ultrasonography were used in a prospective study to differentiate between pituitary-dependent HAC (PDH) and adrenal-dependent HAC (ADH). In 27 out of the 29 dogs (93 per cent), both endogenous plasma ACTH concentrations and adrenal ultrasonography indicated the same cause of HAC. Twenty-one of the 29 cases (72 per cent) were shown to be pituitary-dependent; all had plasma ACTH concentrations of greater than 28 pg/ml (reference range 13 to 46 pg/ml) and both adrenal glands were ultrasonographically of similar size and of normal shape. All 21 cases responded well to mitotane therapy. Six cases (21 per cent) were shown to be adrenal-dependent; all had plasma ACTH concentrations below the limit of the assay (<5 pg/ml) and the presence of an adrenal mass on ultrasonography. The sensitivity and specificity of adrenal ultrasonography and endogenous ACTH determinations to identify the cause of HAC were demonstrated to be 100 per cent and 95 per cent, respectively, for ADH. These discriminatory tests are more accurate than published figures for dexamethasone suppression testing.

Idiopathic telangiectasia in a Golden Retriever

A case report of a 12-year-old spayed female Golden Retriever with a 4-month history of persistent diffuse erythema involving the right and left antebrachia is presented. Cutaneous biopsies revealed superficial dermal vascular dilation and proliferation with moderate epidermal acanthosis. Diagnostic tests failed to reveal an underlying aetiology. Telangiectasia is defined as a permanent dilation of pre-existing blood vessels creating small focal lesions. Generalized essential telangiectasia of humans is common in women of middle-age and can involve entire segments of the body. Lesions predominantly affect the extremities and can persist for years without any systemic effects. The cutaneous lesions in this case have remained static for 3 years with no manifestation of systemic signs. A diagnosis of idiopathic telangiectasia was made based on the clinical and histological findings in the dog of this report. The lesions described in this dog resemble generalized essential telangiectasia of humans.

Ultrasonography of the adrenal glands in the dog, cat, and ferret

Ultrasonography has become an important modality for imaging adrenal glands in small animals. Normal adrenal glands and structural abnormalities, such as changes in size, shape, and echogenicity, can be identified. In the case of adrenal tumors, ultrasonography is a valuable tool for identifying neoplastic masses with local and regional involvement, as well as potential abdominal metastases. When correlated with clinical findings and results of hematologic, serum biochemical and endocrine tests, ultrasonographic findings make a substantial contribution to the diagnosis of adrenal diseases in dogs, cats, and ferrets.

Retrospective ultrasonographic evaluation of adrenal lesions in 26 dogs

A review was performed of ultrasonographic findings in 26 dogs with confirmed adrenal lesions. Adrenal shape, size, echogenicity, laterality, and the presence of vascular invasion were evaluated. Histopathologic diagnoses were obtained in all dogs. Adrenal lesions were confirmed as pheochromocytomas (9), adenocarcinomas (6), a poorly differentiated blastoma (1), bilateral adrenal metastases of a carcinoma (1), adenomas--one of which was bilateral--(4) and hyperplasia (6). Size and shape were extremely variable and not specific to lesion type. There was a tendency for pheochromocytomas (7), adenocarcinomas (5) and poorly differentiated blastoma (1) to be rounded masses. Adenomas (4), hyperplasia (7) and adrenal metastases (2) presented predominantly as nodules. No specificity in echogenicity was noted. Mineralization and bilaterality were present in both benign and malignant lesions. Vascular extension or the presence of a thrombus were suggestive but not specific signs of malignancy. Based on our preliminary study, ultrasonography is an effective method for localizing adrenal lesions and is helpful in assessing their extension. However, no definitive differentiation between benign and malignant lesions was possible using ultrasonographic criteria alone.

Ultrasonographic diagnosis of an adrenocortical carcinoma in a dog

The ultrasonographic findings in a nine-year-old female Drahthaar with an adrenocortical carcinoma of the left adrenal gland are described. Examination of the abdomen revealed a large, hypoechoic mass cranial to the left kidney. Areas of calcification inside the mass and the lateral displacement of the caudal vena cava were assessed. The right adrenal gland was thinner and smaller than normal. Several target-like lesions were present in the hepatic parenchyma. A moderate amount of haemorrhagic abdominal fluid was also present. The ultrasonographic findings were consistent with this type of adrenal neoplasia which produces atrophy of the contralateral gland and frequently metastasises to the liver. The ultrasonographic diagnosis of adrenocortical carcinoma was confirmed by histopathological examination.

Ultrasonographic adrenal gland measurements in dogs without evidence of adrenal disease

The purpose of this retrospective study was to determine measurements of adrenal glands from longitudinal sonograms, in a large population of dogs and to correlate these measurements to age, sex and descriptors of body size. Dogs were selected from the clinic population presented for routine abdominal ultrasonography between September, 1991 and March, 1994. Dogs with elevated serum cholesterol or alkaline phosphatase levels, polyuria/polydipsia, and/or clinical diagnoses of adrenal pathology were excluded. Dogs with ultrasound-documented abnormalities (mass lesions, abnormal architecture) of either adrenal were not considered. Age, sex, weight and breed were recorded, and the body surface area of each dog was calculated. Adrenal length and caudal polar width were determined from longitudinal, two-dimensional ultrasound images. Adrenal measurements were compared with body size measurements and age using least squares linear regression analysis and the correlation coefficient (r) and coefficient of determination (r2) calculated. One hundred and ninety three dogs were included in the study, with a weight and body surface area range of 1.8-72 kg and 0.2-1.8 m2, respectively. The left adrenal gland (n = 182) length range was from 10.7 to 50.2 mm, and the range of the caudal polar widths was 1.9 to 12.4 mm. Right adrenal gland (n = 85) length range was from 10 to 39.3 mm, and the range of the caudal polar widths was from 3.1 to 12 mm. In dogs where both adrenal gland lengths were measured (n = 74), the right adrenal gland length was less than that of the left in 46 dogs, equal to the left in one dog, and greater than the length of the left in 27 dogs. The strongest linear association was noted between the left adrenal gland length and body weight (kg, r = 0.71, p < 0.0001) or body surface area (m2, r = 0.71, p < 0.0001). Similar significant association was noted between the right adrenal gland length and body weight (kg, r = 0.69, p < 0.0001). A significant positive association was also noted between age and left adrenal gland length, (r = 0.25, p = 0.009). The summation of all four adrenal measurement values (left length and width, right length and width) did slightly improve the correlation (r = 0.74, p < 0.0001) when compared with body weight (kg). There was not a significant difference in the adrenal measurements with regard to sex. With regard to the correlation coefficient values, there was no advantage noted to calculating the body surface area from body weight. The causes for the low degrees of the correlation between adrenal size and the variables investigated in this study are unknown; measurement error, effects of non-adrenal illness on adrenal size, and a non-linear or complex linear relationship between adrenal gland size (as measured by longitudinal parameters) and descriptors of body size are among possible explanations.

Adrenal incidentalomas. Diagnostic workup of the incidentally discovered adrenal mass

The incidentally discovered adrenal mass is a diagnostic dilemma veterinarians are likely to face with increasing frequency in the coming years. Dogs and cats may be more prone to functional adrenal lesions than are humans. Most adrenal tumors are benign, but a significant number of adrenocortical carcinomas (approximately 12%) and metastatic lesions within the adrenal glands (3% to 34%) do occur. Evaluation for hypertension, hypokalemia, and loss of hypothalamic-pituitary-adrenal responsiveness to a low dose of dexamethasone is appropriate for all patients with adrenal incidentalomas. The value of clinical and historical signs of hormonal overexpression should not be underestimated. More invasive or expensive diagnostic testing should be predicted on suspicions raised by the history and clinical signs. New diagnostic clinicopathologic tests, including plasma CgA and serum DHEAS, should be investigated in veterinary patients. Advanced diagnostic imaging using nuclear scintigraphy and chemical-shift MRI may offer veterinarians sensitive and specific noninvasive tools to consider for the evaluation of these patients. Patients with large masses, tumors with signs of malignancy, or productive adrenal tumors (plus or minus cortisol-producing tumors in which chemical ablation with mitotane can be attempted) should be considered candidates for exploratory surgery.

Imaging of adrenal gland disorders

In recent years, diagnostic imaging has become an important adjunct to conventional endocrine testing in the evaluation of adrenal gland dysfunction. This article discusses the role of imaging in the diagnostic workup of the following adrenal gland disorders: hypercatacholaminism, hyperaldosteronism, hyperadrenocorticism, and hypoadrenocorticism. The strengths and limitations of radiography, ultrasonography, scintigraphy, CT scanning, and MR imaging are addressed.

Ultrasonographic characteristics of the adrenal glands in dogs with pituitary-dependent hyperadrenocorticism: comparison with normal dogs

Ultrasonographic evaluation of the adrenal glands was performed in 10 dogs with pituitary-dependent hyperadrenocorticism (PDH) and in 10 age- and weight-matched healthy control dogs. Thickness, shape, and echogenicity were determined for each adrenal gland. Adrenal thickness in dogs with PDH (median, 10 mm-left; 8.5 mm-right) was significantly greater than thickness in control dogs (median, 6 mm-left; 6 mm-right). Other ultrasonographic characteristics associated with PDH included bilaterally symmetrical adrenomegaly and maintenance of normal adrenal shape. Adrenal echogenicity was homogeneous and less than that of the adjacent renal cortex in 8 of 10 dogs with PDH and in 10 of 10 control dogs. Heterogenous echogenicity was present in 2 of 10 dogs with PDH, and was associated with nodular cortical hyperplasia in one of those dogs. Results of this study confirm the difference in sonographic appearance between PDH-induced bilateral cortical hyperplasia and functional adrenocortical neoplasia, and show a difference in sonographically determined adrenal size between healthy dogs and dogs with PDH.

Surgical treatment of pheochromocytoma: technique, complications, and results in six dogs

Six dogs were diagnosed with pheochromocytoma and staged according to the World Health Organization's system for tumor classification. Two dogs had benign tumors (T1, N0, M0) and four dogs had malignant tumors (T2, N0, M1 or T3, N0, M0). All dogs had adrenalectomy, two dogs had concurrent nephrectomy, and three dogs had concurrent resection of a tumor thrombus from the vena cava. Anesthetic complications occurred in five dogs, including wide variations in heart rate (four dogs), blood pressure (five dogs), and cardiac arrhythmias (one dog). One dog died 12 hours after surgery from partial dehiscence of the suture line and hemorrhage from the vena cava, and one dog died 6 days after surgery during general anesthesia for treatment of laryngeal paralysis. Four dogs survived from 3 to 23 months (median, 15 months). One dog remained hypertensive after surgery. Benign and malignant pheochromocytomas seem to be amenable to surgical resection.

Pheochromocytoma in 50 dogs

Fifty dogs with pheochromocytoma were identified in a retrospective study of a 9-year period. For 24 of 50 dogs (48%), the tumor was an incidental finding during necropsy or surgery. Presenting signs were referrable to the nervous system in 7 of the 26 symptomatic dogs (27%); were referrable to the cardiopulmonary system in 7 of 26 dogs (27%); or were nonspecific, reflecting general systemic disease, in 17 of 26 dogs (65%). Abnormal clinical findings were highly varied but were also generally referrable to the cardiopulmonary and nervous systems. Six of 7 dogs (86%) evaluated were hypertensive (systolic range, 164 to 325 mm Hg; diastolic range, 110 to 198 mm Hg). Serum biochemical findings were nonspecific, although 11 of 39 dogs (28%) were hypercholesterolemic. Abdominal fluid samples were analyzed in 6 dogs; 3 were nondiagnostic, and 3 were interpreted as lymphosarcoma. The imaging studies that were of most value included abdominal radiographs (mass identified in 9 of 16 dogs [56%]), caudal vena caval angiography (tumor thrombus correctly diagnosed in 4 of 7 dogs [57%]), and abdominal ultrasonography (mass seen in 5 of 6 dogs [83%] and tumor thrombus seen in 3 of 5 dogs [60%]). Local tumor invasion was present in 26 of 50 dogs (52%), regional lymph node metastases in 6 of 50 dogs (12%), and distant metastases in 12 of 50 dogs (24%). Cause of death was tumor-related in 19 of 50 dogs (38%) and non-tumor related in 28 of 50 dogs (54%).

Ultrasonography

The basic principles of diagnostic ultrasonography are discussed. Normal and abnormal ultrasonographic appearances of the major organs are presented in tables and with illustrations. A description of the current status of neurosonology with illustrations of hydrocephalus is also presented.

Canine hyperadrenocorticism due to adrenocortical neoplasia. Pretreatment evaluation of 41 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 at least one measurement (less than 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.(ABSTRACT TRUNCATED AT 250 WORDS)