Surgical management of adrenal gland tumors with and without associated tumor thrombi in dogs: 40 cases (1994-2001)

Successful laparotomic ethanol ablation for an adrenal tumour in a dog

Adrenalectomy is the gold standard for canine adrenal tumours, but not always recommended due to patient age, underlying conditions and perioperative mortality. Ethanol ablation is an alternative in human medicine for poor surgical candidates. A 13-year-old neutered female toy-poodle with hypercortisolism presented with severe haematuria. Ultrasonography revealed left adrenal and right kidney tumours. Due to high surgical risk, simultaneous laparotomic right nephroureterectomy and ethanol ablation of the left adrenal tumour were performed. Post-ethanol injection complications included transient hypertension and arrhythmia, which resolved spontaneously. The adrenal tumour size decreased within 2.5 months, and cortisol levels normalised within 8 days, remaining stable for 12 months. No hypercortisolism signs were observed without trilostane until death from renal insufficiency. Autopsy showed that the ablated left adrenal gland was an adrenocortical tumour and had shrunk. Ethanol ablation may be a feasible alternative to adrenalectomy for high-risk canine patients.

Computed tomographic anatomic variations of the phrenicoabdominal veins in cats

There are no published reports describing the anatomic variations of the phrenicoabdominal (PhAbd) veins in cats. The aim of this study was to evaluate the anatomic variations of the PhAbd veins in cats without adrenal disease. This is an anatomic study. Abdominal CT images of cats acquired from January 2021 to February 2023 were retrospectively reviewed. Inclusion criteria were the presence of pre- and postcontrast CT images of the abdomen and the absence of any abdominal diseases that compromise the left and right PhAbd veins visualization. A total of 128 cats were included. Three different vascular anatomic variations were found in the distal pericaval segment of the left phrenicoabdominal (LPhAbd) vein. In the first type, found in 65 cases (50.8%), the LPhAbd vein drained directly into the caudal vena cava. In the second type defined IIa, found in 25 cases (19.5%), the LPhAbd vein drained into the distal third of the left renal vein, less than 5 mm from its opening into the caudal vena cava. In the third type defined IIb, found in 38 cases (29.7%), the LPhAbd vein drained into the distal third of the left renal vein, more than 5 mm from its opening into the caudal vena cava. The right phrenicoabdominal vein had a consistent path and drained into the caudal vena cava in all cases. The knowledge of these vascular variations is expected to help the surgeon during adrenalectomy due to masses with vascular invasion in cats.

Laparoscopic vs. open adrenalectomy: perioperative data and survival analysis in 70 dogs with an adrenal tumor

Adrenalectomy is the treatment of choice in case of functional adrenal tumors and malignant adrenal incidentalomas. Laparoscopic adrenalectomy (LA) in dogs has gained popularity in recent years, however, clinical studies on large patient populations are scarce. This retrospective study describes perioperative and recurrence data, survival, and prognostic factors in 70 dogs that underwent LA or open adrenalectomy (OA) in our hospital between 2008 and 2022. Diagnosis was based on history, clinical signs, endocrine function tests and advanced diagnostic imaging. Laparoscopic adrenalectomy was performed in 42 dogs (n = 27 naturally occurring hypercortisolism, n = 4 pheochromocytoma, n = 1 pheochromocytoma with concurrent hypercortisolism, n = 10 incidentaloma) and OA in 28 dogs (n = 22 hypercortisolism, n = 3 pheochromocytoma, n = 3 incidentaloma). Bilateral adrenalectomy was performed in 8/70 dogs. Surgical duration of LA and OA did not differ significantly in unilateral and bilateral procedures (P = 0.108 and P = 0.101, respectively). Systemic hypertension occurred in 7/41 and 1/28 dogs during LA and OA, respectively (P = 0.130). Hypotension occurred in 2/41 and 4/28 dogs during LA and OA, respectively (P = 0.214). A total of 40/42 dogs in the LA group and 27/28 in the OA group survived to discharge (P = 0.810). Mean hospital stay was significantly shorter (P = 0.006) after LA (1.5 days, range 1-3) than after OA (2.2 days, range 1-4). No significant differences were demonstrated between LA and OA groups in recurrence of adrenal-dependent endocrine disease (P = 0.332), disease-free period (P = 0.733) and survival time (P = 0.353). The disease-specific 1-, 2- and 3-year survival rates were 95, 89, and 89% after LA and 92, 88, and 81% after OA. Tumor size was significantly associated with the occurrence of a recurrence. In addition, tumor size had a negative effect on the disease-free period and survival time. This study shows a favorable outcome of both LA and OA in dogs. Based on low perioperative complication rate, short hospitalization time and long-term outcomes comparable to OA in selected cases, the less invasive laparoscopic approach is considered the preferred technique.

Preemptively planned en bloc resection of an extensive right adrenal pheochromocytoma involving the right hepatic division, caval thrombus and segmental caudal vena cava in a dog with Budd-Chiari-like syndrome

BACKGROUND

Surgical resection is the treatment of choice for canine adrenal pheochromocytomas (PHEOs). Information on en bloc resection of adrenal PHEO with tumour thrombus, right hepatic division and segmental caudal vena cava (CVC) running through the adrenal tumour and right hepatic division is limited.

OBJECTIVE

To describe the preemptively planned en bloc resection of an extensive right adrenal PHEO involving the right hepatic division, the caval thrombus and the segmental CVC in a dog with Budd-Chiari-like syndrome (BCLS).

METHODS

A 13-year-old castrated male miniature dachshund was referred for surgical treatment due to anorexia, lethargy and severe abdominal distension caused by abundant ascites. Preoperative computed tomography (CT) revealed a large mass in the right adrenal gland with a large caval thrombus obstructing the CVC and hepatic veins, which caused BCLS. Additionally, collateral vessels were formed between the CVC and azygos veins. No findings suggested obvious metastases. Based on CT findings, an en bloc resection of the adrenal tumour with caval thrombus, right hepatic division and segmental CVC was planned.

RESULTS

The preoperatively planned resection was feasible; the tumour was completely resected grossly. The operation time and total Pringle manoeuvre time were 162 min and 16 min 56 s, respectively. There was no postoperative hindlimb oedema, renal dysfunction, ascites or abdominal distention. The patient's clinical signs, including appetite, fully improved. Hospitalization lasted 16 days. However, the patient died on the 130th postoperative day due to suspected metastases and cachexia.

CONCLUSIONS

Even in case of an extensive infiltration of adrenal PHEO causing BCLS, an en bloc resection might be successfully achieved based on the preoperative CT findings speculating the collateral vessels formed for caudal venous return.

Stereotactic body radiation therapy as an alternative to adrenalectomy for the treatment of pheochromocytomas in 8 dogs

The objective of this report is to describe the use and outcome of stereotactic body radiation therapy (SBRT) for treatment of pheochromocytomas in 8 dogs. Pheochromocytomas are an uncommon but challenging tumour to manage. Adrenalectomy is the standard of care for treatment of pheochromocytomas in both animals and humans; however, unpredictable catecholamine secretion from the tumour and vascular and local invasion of the tumour and thrombi can pose life-threatening perioperative and anaesthetic risks. SBRT has been investigated as an alternative to adrenalectomy in human patients with pheochromocytomas. Eight dogs with clinical signs, an adrenal mass, and cytology and/or urine normetanephrine/creatinine ratios consistent with pheochromocytoma were treated with SBRT in lieu of adrenalectomy. Three dogs presented with acute hemoabdomen. Seven dogs had caval tumour invasion, 3 with extension into the right atrium. Following SBRT, all dogs had complete resolution of clinical signs and reduced urine normetanephrine/creatinine ratio and/or tumour size. No significant anaesthetic complications were encountered. Acute radiation toxicity was limited to grade I gastrointestinal signs in 3 dogs and resolved within 1-2 days of symptomatic therapy. Five of 8 dogs were alive at the time of follow up, with a median follow up time of 25.8 months. SBRT resulted in a favourable outcome and mitigated the life-threatening risks of adrenalectomy in these 8 dogs. SBRT may be a safe and effective alternative to adrenalectomy for pheochromocytomas in dogs with non-resectable tumours, or for owners averse to the risks of surgery.

Balloon catheter as an extraction device for caudal vena cava adrenal tumor thrombectomy in a dog: A case report

OBJECTIVE

To report the use of a balloon catheter as an extraction device for a posthepatic caval thrombus in a dog with a right adrenal tumor.

ANIMALS

Twelve-year-old male neutered Chihuahua mix dog.

STUDY DESIGN

Case report METHODS: The dog presented for the evaluation of a hepatic mass. Computed tomography of thorax and abdomen was performed, and a right lateral liver lobe mass and a right adrenal mass were noted. The adrenal mass had a caval thrombus extending almost to the level of the right atrium. Traditional methods of tumor thrombectomy were unsuccessful. Extraction of the thrombus was facilitated by passing a balloon catheter through the caudal vena cavotomy until it was cranial to the thrombus, inflating the balloon and slowly withdrawing the catheter.

RESULTS

A malignant pheochromocytoma was diagnosed on histology. The dog had a subjectively assessed good quality of life until it was euthanized 118 days postoperatively for acute dyspnea.

CONCLUSION

Balloon catheter-assisted thrombectomy was successful in removing an extensive caval thrombus that was otherwise difficult to extract via conventional methods. This technique can be considered in cases with extensive tumor thrombus either as a method of choice or when other methods of thrombus extraction have failed.

Anaesthetic Management of a Labrador Retriever Undergoing Adrenalectomy for Phaeochromocytoma Excision, a Case Report

Perioperative management of cases undergoing phaeochromocytoma removal should aim at normalising blood pressure and heart rate, restoring volume depletion, and preventing catecholamine release induced by surgical manipulation. In this case report, a novel pharmacological approach in a dog undergoing surgical tumour excision is described. A 7-year-old 25-kg spayed female Labrador Retriever presented for repeated episodes of generalised weakness, pale mucous membranes, tachycardia, tremor, panting, vomiting, and hypertension over the last month was referred for surgical treatment of a left-sided adrenal tumour with invasion of the caudal vena cava. Severe hypertensive episodes occurred repeatedly, starting early during the anaesthetic period, while clipping and cleaning the abdominal area, and continued intraoperatively when the tumour was handled. Moderate hypotension occurred once the tumour was isolated and worsened during temporary caudal vena cava flow interruption and cavotomy. The patient was treated preoperatively with phenoxybenzamine to prevent hypertensive crises. Intraoperatively, magnesium sulphate and urapidil were used to control blood pressure. This treatment was effective in reducing the magnitude of blood pressure spikes but not sufficient to prevent hypertensive peaks, especially during tumour manipulation. Hypotension was treated with synthetic colloid and crystalloid boli, and noradrenaline continuous infusion. Blood transfusion was performed in response to acute bleeding during cavotomy. The dog recovered successfully from anaesthesia and its quality of life was deemed excellent by the owner at the last follow up, 22 months after surgery. The histopathology confirmed the diagnosis of phaeochromocytoma with an invasion of the phrenicoabdominal vein. In the present case, we obtained a successful outcome but failed to provide haemodynamic stability throughout the procedure.

Prediction of vascular invasion using a 7-point scale computed tomography grading system in adrenal tumors in dogs

BACKGROUND

Previous studies evaluating the accuracy of computed tomography (CT) in detecting caudal vena cava (CVC) invasion by adrenal tumors (AT) used a binary system and did not evaluate for other vessels.

OBJECTIVE

Test a 7-point scale CT grading system for accuracy in predicting vascular invasion and for repeatability among radiologists. Build a decision tree based on CT criteria to predict tumor type.

METHODS

Retrospective observational cross-sectional case study. Abdominal CT studies were analyzed by 3 radiologists using a 7-point CT grading scale for vascular invasion and by 1 radiologist for CT features of AT.

ANIMALS

Dogs with AT that underwent adrenalectomy and had pre- and postcontrast CT.

RESULTS

Ninety-one dogs; 45 adrenocortical carcinomas (50%), 36 pheochromocytomas (40%), 9 adrenocortical adenomas (10%) and 1 unknown tumor. Carcinoma and pheochromocytoma differed in pre- and postcontrast attenuation, contralateral adrenal size, tumor thrombus short- and long-axis, and tumor and thrombus mineralization. A decision tree was built based on these differences. Adenoma and malignant tumors differed in contour irregularity. Probability of vascular invasion was dependent on CT grading scale, and a large equivocal zone existed between 3 and 6 scores, lowering CT accuracy to detect vascular invasion. Radiologists' agreement for detecting abnormalities (evaluated by chance-corrected weighted kappa statistics) was excellent for CVC and good to moderate for other vessels. The quality of postcontrast CT study had a negative impact on radiologists' performance and agreement.

CONCLUSIONS AND CLINICAL IMPORTANCE

Features of CT may help radiologists predict AT type and provide probabilistic information on vascular invasion.

Short- and long-term survival after adrenalectomy in 53 dogs with pheochromocytomas with or without alpha-blocker therapy

OBJECTIVE

To report data related to the short- and long-term survival of dogs undergoing adrenalectomy for pheochromocytoma, and to determine the influence of preoperative alpha-blocker therapy.

STUDY DESIGN

Retrospective.

ANIMALS

Fifty-three dogs.

METHODS

Medical records were reviewed for dogs diagnosed with pheochromocytoma and treated with adrenalectomy between 2010 and 2020. Preoperative management, imaging studies, intraoperative cardiovascular instability, complications, and procedural information were recorded. When applicable, duration of survival and cause of death, time to recurrence or metastasis, and postoperative complications were recorded.

RESULTS

During anesthesia, a hypertensive episode was documented in 46/53 dogs and arrhythmias were recorded in 16/53 dogs. Of these, 37/46 hypertensive dogs and 11/16 dogs with arrhythmias were treated with an alpha-blocker before surgery. Intraoperative systolic blood pressures reached higher levels by a magnitude of nearly 20% in dogs that were treated preoperatively with an alpha-blocker (P = .01). All dogs survived surgery and 44 survived to discharge. Follow up ranged from 6 to 1653 days (median 450 days). Median survival time for dogs discharged from the hospital was 1169 days (3.2 years). Recurrence and metastasis were suspected in 3 and 8 dogs, respectively.

CONCLUSION

Most dogs survived the immediate postoperative period and achieved long-term survival with a low reported incidence of tumor recurrence or metastasis. Preoperative alpha-blocker therapy was not associated with increased survival.

CLINICAL SIGNIFICANCE

The favorable outcomes reported in this study should be taken into consideration when discussing treatment options for dogs with pheochromocytomas. This study provides no evidence to support preoperative alpha-blocker therapy.

18F-FDG PET/CT image findings of a dog with adrenocortical carcinoma

Background

In human medicine, 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) has been used to differentiate between benign and malignant adrenal tumors and to identify metastases. However, canine adrenocortical carcinomas identified by 18F-FDG PET/computed tomography (CT) have not been reported.

Case presentation

A 13-year-old, castrated male, Cocker Spaniel dog with severe systolic hypertension exhibited an adrenal mass approximately 3.6 cm in diameter on ultrasonography. There was no evidence of pulmonary metastasis or vascular invasion on thoracic radiography and abdominal ultrasonography, respectively. 18F-FDG PET/CT was performed to identify the characteristics of the adrenal mass and the state of metastasis. One hour after injection of 5.46 MBq/kg 18F-FDG intravenously, the peripheral region of the adrenal mass visually revealed an increased 18F-FDG uptake, which was higher than that of the liver, and the central region of the mass exhibited necrosis. The maximal standardized uptake value (SUV) of the adrenal mass was 3.24; and relative SUV, calculated by dividing the maximal SUV of the adrenal tumor by the mean SUV of the normal liver, was 5.23. Adrenocortical carcinoma was tentatively diagnosed and surgical adrenalectomy was performed. Histopathologic examination of the resected adrenal mass revealed the characteristics of an adrenocortical carcinoma. After adrenalectomy, systolic blood pressure reduced to below 150 mmHg without any medication.

Conclusion

This is the first case report of 18F-FDG PET/CT findings in a dog with suspected adrenocortical carcinoma and may provide valuable diagnostic information for adrenocortical carcinoma in dogs.

CT measures of adrenal gland length and caudal pole diameter are reproducible in large breed dogs: A pilot study

Computed tomography (CT) is increasingly available to evaluate dogs with suspected adrenal disease, however, published studies describing the reproducibility of CT methods for quantifying adrenal gland (AG) measurements are lacking. This prospective, pilot, observer agreement study aimed to evaluate reproducibility and repeatability of two different methods of measurement of AGs on CT to establish a usable technique and define standard reference ranges. Multiplanar reformatted (MPR) CT images of both AGs of six large breed dogs were obtained with the MPR axis parallel to the spine and parallel to the long axis of the AG. Ten measurements were performed: maximal length and diameter at cranial and caudal poles on dorsal, sagittal, and transverse images; and minimal diameter of cranial and caudal poles on transverse images. Three observers with different levels of experience repeated these measurements three times for each dog. Intra‐ and interobserver variability were calculated through intraclass correlation coefficient (ICC). The differences in time to perform measurements between the two methods were tested with Student's t‐test. Regardless of the measurement method used, length of AGs on dorsal and sagittal MPR images had the lowest intra‐ and inter‐observer variability (ICC = 0.93‐0.99), diameter of caudal pole on transverse plane showed low intra‐ and interobserver variability (ICC = 0.77‐0.80) and diameter of cranial pole had the highest variability (ICC = 0.12‐0.61). Although length was the less variable measurement, its use may be unrealistic in daily practice. Interestingly measurement of caudal pole on transverse plane was characterized by low intra‐ and interobserver variability. No difference in time performing the measurements was noted between the two methods.

Urinary free metanephrines measurement in dogs with adrenal gland diseases using a new simple liquid chromatography tandem mass spectrometry method

Measurement of urinary metanephrines in spot samples is used for the diagnosis of canine pheochromocytoma (PC). We describe a simple analytical method based on liquid chromatography tandem mass spectrometry (LC-MS/MS) for measuring free metanephrine (MN) and normetanephrine (NMN) in spot urine samples. Using the developed method, we evaluated the stability of urinary free-MN and free-NMN at various storing conditions. In addition, we assessed the feasibility of urinary free-MN and -NMN measurement for diagnosing PC. Urine samples were mixed with stable isotope internal standards and thereafter purified by ultrafiltration. The purified samples were analyzed by LC-MS/MS in the multiple reaction monitoring mode after separation on a multimode octa decyl silyl column. The coefficient of variation of free-MN and -NMN measurement was 7.6% and 5.5%, respectively. The linearity range was 0.5–10 µg/l for both analytes. Degradation was less than 10% for both analytes under any of the storage conditions. The median free-NMN ratio to creatinine of 9 PC dogs (595, range 144–47,961) was significantly higher (P<0.05) than that of 13 dogs with hypercortisolism (125, range 52–224) or 15 healthy dogs (85, range 50–117). The developed method is simple and may not require acidification of spot urine. The results of this preliminary retrospective study suggest that the measurement of urinary free metanephrines is a promising tool for diagnosing canine PC.

Renal venotomy for thrombectomy and kidney preservation in dogs with adrenal tumors and renal vein invasion

OBJECTIVE

To describe the surgical technique and report the outcomes of adrenalectomy and thrombus removal with kidney preservation by renal venotomy in a population of dogs with adrenal tumors and vascular invasion into the renal vein (RV) and caudal vena cava (CVC).

STUDY DESIGN

Short case series.

ANIMALS

Five client-owned dogs that underwent adrenalectomy.

METHODS

Dogs with adrenal tumors and vascular invasion into the RV and CVC were retrospectively enrolled in this multi-institutional study. Renal venotomy was performed at the time of adrenalectomy for tumor thrombus removal. Recorded data included signalment, clinical signs and results of laboratory testing, physical examination findings, diagnostic imaging results, surgical technique, surgical time, surgical complications, and outcome.

RESULTS

Tumor thrombus was removed by renal venotomy in five dogs. In one dog with an ectopic adrenal tumor located ventral to the left kidney, the thrombus was occluding 90% of caval flow, and a small caval venotomy was required to remove it. Kidney preservation was achieved in all dogs. No significant intraoperative or postoperative complications occurred, and all dogs were discharged 3 to 4 days postoperatively. Median surgical time was 125 minutes (range, 80-210). At the end of the study, four dogs were alive without signs of recurrence, while one dog died of a suspected pulmonary embolism at 510 days. Median follow-up was 510 days (range, 279-890).

CONCLUSION

Renal venotomy is feasible for thrombectomy in dogs with adrenal tumors and RV invasion and allowed for the preservation of the kidney in this case series, thus limiting perioperative morbidity.

A comparison of outcomes between laparoscopic and open adrenalectomies in dogs

OBJECTIVE

To compare short- and long-term outcomes of dogs with adrenal tumors treated by adrenalectomy with laparoscopy or laparotomy.

STUDY DESIGN

Retrospective study of dogs that underwent adrenalectomy with laparoscopy or laparotomy.

SAMPLE POPULATION

Fourteen dogs treated with laparoscopic adrenalectomy (LA) and twenty-six dogs treated with open midline adrenalectomy (OA).

METHODS

Dogs treated with LA were matched with 1 or 2 dogs treated with OA on the basis of histological nature, size, and side of the tumor. Intraoperative complications, postoperative complications, and long-term survival were compared between LA and OA.

RESULTS

Intraoperative hypotension occurred in 2 of 14 (14.3%) dogs in the LA group and in 16 of 26 (61.5%) dogs in the OA group (P = .007). The surgical time was 69.8 ± 21.8 minutes for the LA group and 108.6 ± 42 minutes for the OA group (P = .0003). The hospitalization time was 39.3 ± 14.9 hours for the LA group and 46.3 ± 25.1 hours for the OA group (P = .1453). The 1- and 2-year survival rates were 77% and 77%, respectively, for the LA group and 77% and 66%, respectively, for the OA group (P = .6144).

CONCLUSION

Laparoscopic adrenalectomy was associated with a shorter surgical time and a reduced incidence of hypotension compared with open adrenalectomy in this case-matched study. Short- and long-term outcomes were not affected by the surgical technique used to complete the adrenalectomy.

CLINICAL SIGNIFICANCE

Laparoscopy can be recommended for adrenalectomy in dogs; however, appropriate case selection is required.

Feline abdominal ultrasonography: what's normal? what's abnormal? The adrenal glands

PRACTICAL RELEVANCE

Abdominal ultrasound plays a vital role in the diagnostic work-up of many cats presenting to general and specialist practitioners. Ultrasound examination of the adrenal glands can provide important information pertaining to several conditions including hyperaldosteronism and hyperadrenocorticism.

CLINICAL CHALLENGES

Despite ultrasonography being a commonly used modality, many practitioners are not comfortable performing an ultrasound examination or interpreting the resulting images. Even for the experienced ultrasonographer, differentiating between incidental findings, such as adrenal mineralisation, and clinically significant pathological changes can be challenging.

AIM

This review, part of an occasional series on feline abdominal ultrasonography, discusses the ultrasonographic examination of the normal and diseased adrenal glands. Aimed at general practitioners who wish to improve their knowledge of and confidence in feline abdominal ultrasound, this review is accompanied by high-resolution images and videos available online as supplementary material.

EQUIPMENT

Ultrasound facilities are readily available to most practitioners, although the use of ultrasonography as a diagnostic tool is highly dependent on operator experience.

EVIDENCE BASE

Information provided in this article is drawn from the published literature and the author's own clinical experience.

Utility of contrast-enhanced ultrasound in differential diagnosis of adrenal tumors in dogs

This prospective case study aimed to clarify the clinical significance of contrast-enhanced ultrasound (CEUS) for the differential diagnosis of canine adrenal tumors. Forty-three client-owned dogs with adrenal tumors were included. All dogs underwent CEUS, which was evaluated qualitatively and quantitatively. The peak signal intensity (PI), time to peak signal intensity (TPI), mean transit time (MTT), upslope, and downslope were calculated for each time-intensity curve. The histopathological diagnosis of each resected mass was compared with the CEUS findings and parameters. Enhancement distribution, vascularity, tortuous nourishing vessels, enhancement pattern, and late-phase enhancement did not differ significantly between adrenal cortical adenoma (CA), adenocarcinoma (CAC), and pheochromocytoma (PHEO) in qualitative assessment. In PHEO, the TPI was significantly more rapid compared with that in CA (P=0.0287) and CAC (P=0.0404). The MTT in PHEO was significantly shorter than that in CA (P=0.0016) and CAC (P=0.0003). Upslope in PHEO was larger than that in CAC (P=0.0406). Downslope in PHEO was significantly larger than that in CA (P=0.0048) and CAC (P=0.0018). A receiver operating characteristic curve analysis demonstrated that the area under the MTT curve yielded 0.91 for distinguishing PHEO from adrenocortical tumors in dogs; an MTT cut-off value less than 6,225 msec yielded a sensitivity of 69%, specificity of 94%, and likelihood ratio of 12.46. CEUS appears to be clinically applicable for the differential diagnosis between cortical and medullary origins of primary adrenal tumors in dogs.

Use of Contrast-Enhanced Ultrasonography for the Characterization of Tumor Thrombi in Seven Dogs

Simple Summary

Some neoplasia—such as adrenal and thyroid glands tumors—have been associated with “tumor thrombi” both in humans and dogs. The detection and characterization of these venous tumor thrombi is important for both surgical planning and prognosis. In human medicine, contrast-enhanced ultrasonography (CEUS) is considered an accurate diagnostic technique for differentiating malignant from benign portal vein thrombosis in hepatocellular carcinomas. Data regarding the characteristics of tumor thrombi in dogs are currently lacking. Therefore, the aim of this study was to assess the feasibility of CEUS for the characterization of malignant venous thrombosis in dogs. On the basis of our results, CEUS appeared to be useful in the detection of malignant intravascular invasion; contrast uptake of the thrombus was present in all cases. In addition, CEUS may clearly detect newly formed vessels within the thrombus, and arterial-phase enhancement and washout in the venous phase were the main features in malignant thrombosis in our dogs. As CEUS is an easy to perform, noninvasive technique, its application in the detection of malignant thrombosis in dogs may be used to improve the diagnosis in oncological canine patients.

Abstract

Tumors of adrenal and thyroid glands have been associated with vascular invasions—so-called tumor thrombi, both in humans and dogs. The detection and characterization of venous thrombi is an important diagnostic step in patients with primary tumors for both surgical planning and prognosis. The aim of this study was to describe the use of contrast-enhanced ultrasonography (CEUS) for the characterization of tumor thrombi. Dogs with tumor thrombus who underwent bi-dimensional ultrasound (B-mode US) and CEUS were included. Seven dogs were enrolled in this retrospective case series. On B-mode US, all thrombi were visualized, and vascular distension and thrombus-tumor continuity were seen in three and two cases, respectively. On color Doppler examination, all thrombi were identified, seemed non-occlusive and only two presented vascularity. On CEUS, arterial-phase enhancement and washout in the venous phase were observed in all cases. Non-enhancing areas were identified in the tumor thrombi most likely representing non-vascularized tissue that could potentially be embolized in the lungs after fragmentation of the tumor thrombi. On the basis of these preliminary study, CEUS appeared to be useful for the characterization of malignant intravascular invasion.

Obstructive shock caused by right atrial thrombosis secondary to malignant pheochromocytoma in a dog

BACKGROUND

Obstructive shock can be caused by any lesion leading to extraluminal compression or intraluminal occlusion of the cardiac chambers or major vessels.

CASE REPORT

A 12-year-old, male castrated, Border Collie cross dog presented to a veterinary teaching hospital for collapse. A physical examination revealed severe vasoconstrictive shock and abdominal distension. Abnormalities on blood tests were consistent with systemic hypoperfusion. Cardiac underfilling, hepatomegaly with distended vasculature and ascites were identified by focused ultrasonography, raising suspicion of obstructive shock. This was supported by the radiographic findings of microcardia and a distended caudal vena cava (CVC). There was transient response to fluid therapy for blood volume expansion. Repeat focused ultrasonography during rapid intravenous fluid administration identified a right intra-atrial mass, assessed as likely to be causing obstruction of venous return. The dog was humanely euthanased given the guarded prognosis. At postmortem evaluation, a malignant pheochromocytoma in the left adrenal gland with tumour thrombus extending to the tricuspid valve through the CVC was found. The extensive thrombus caused the obstructive shock in this case. Metastasis in a peripheral lymph node and neoplastic emboli in the heart and lungs were also visible at the histopathological evaluation.

CONCLUSION

To the best of authors' knowledge, this is the first report of severe obstructive shock secondary to extension of caval tumour thrombus into the right atrium in a dog with malignant pheochromocytoma. Tumour thrombus from a malignant pheochromocytoma should be included as a differential diagnosis of obstructive shock, with or without a visible right intra-atrial mass, in dogs. Serial focused ultrasonography during intravenous fluid administration can aid diagnosis.

Surgical management of an adrenal gland tumor that had extended into the thoracic portion of the caudal vena cava in a dog

CASE DESCRIPTION

A 14-year-old neutered female Border Collie with a 3-week history of collapse during exercise was evaluated because of recumbency, tachycardia, and hypotension.

CLINICAL FINDINGS

Results of biochemical testing indicated the presence of a pheochromocytoma, and CT revealed an enlarged right adrenal gland mass that extended down the right phrenicoabdominal vein into the posthepatic thoracic portion of the caudal vena cava.

TREATMENT AND OUTCOME

A midline celiotomy and median sternotomy were performed to allow en bloc removal of the right adrenal gland tumor and its tumor thrombus extension within the caudal vena cava. Temporary occlusion of the thoracic and abdominal portions of the caudal vena cava and both renal veins and the dual inflow to the liver (Pringle maneuver) were required. The venotomy and tumor and thrombus extractions required a 25-minute period of vascular occlusion. The dog had no major postsurgical complications. Histologic findings indicated that direct adrenal tumor invasion into the caudal vena cava wall had occurred along the established route of tumor extension down the phrenicoabdominal vein.

CLINICAL RELEVANCE

For the dog of this report, an adrenal tumor thrombus that extended into the thoracic portion of the caudal vena cava was surgically managed with a combined median sternotomy and midline celiotomy approach and temporary occlusion of the hepatic artery, portal vein, and abdominal and thoracic portions of the caudal vena cava. This facilitated successful manual manipulation of the tumor and enabled venotomy of sufficient size for tumor thrombus extraction.

Short-term outcome of adrenalectomy in dogs with adrenal gland tumours that did not receive pre-operative medical management

OBJECTIVE

Review medical records of dogs that underwent adrenalectomy without pre-operative medical management, to examine the peri-operative morbidity and mortality.

DESIGN

Case series of 65 dogs.

METHODS

Medical records were reviewed. Features recorded included the histologic diagnosis, intra-operative hypertension or tachycardia, requirement for cavotomy, administration of intra- and post-operative corticosteroids, performance of additional surgery and the occurrence of peri-operative complications. Dogs requiring emergency surgery were excluded.

RESULTS

Of the 65 dogs, 49 had adrenocortical tumours (11 bilateral), 13 had pheochromocytomas (one bilateral) and three dogs had tumours in both adrenal glands of a different tumour type. Five dogs had caudal vena cava invasion and 33 had additional procedures performed at the same time. Mortality occurred in 1/65 dogs (1.5%; 95% CI 0.03%-8.2%), major complications were identified in 1/65 dogs (1.5%; 95% CI 0.03%-8.2%) and minor complications occurred in 10/53 dogs (15%; 95% CI 8.6%-26%).

CONCLUSION

Based on the limited peri-operative complications and low mortality in this pre-operatively untreated cohort, and based on critique of the available literature, the added value afforded by pre-operative treatment is questioned. With appropriate management, adrenal tumours can be removed with few peri-operative complications and low mortality.

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.

Safety of percutaneous ultrasound-guided fine-needle aspiration of adrenal lesions in dogs: Perception of the procedure by radiologists and presentation of 50 cases

Background

Percutaneous ultrasound (US)‐guided fine‐needle aspiration (FNA) of adrenal gland lesions is controversial in veterinary medicine.

Objective

To evaluate the frequency and radiologists' perception of the risk of the procedure as well as determining the incidence of complications.

Methods

Retrospective study. A first survey was submitted by e‐mail to all board‐certified radiologists of the American College of Veterinary Radiology (ACVR) and European College of Veterinary Diagnostic Imaging (ECVDI). A second survey was sent to radiologists who declared having performed the procedure at least once in their career (observational cross‐sectional case study).

Results

The first survey was sent to 977 diplomates and answered by 138. Of 138 diplomates, 40 currently performed the procedure and 98 did not; 44 of the 98 gave the hypertensive crisis risk in pheochromocytoma as a reason. To the second survey, 12 of 65 responded positively; 50 dogs with 58 lesions were recruited, including 23 pheochromocytomas. Complications were reported in 4 of 50 dogs; 3 hemorrhages (1 mild and 1 moderate) and 1 death from acute respiratory distress syndrome (possibly related to laryngeal paralysis). No hypertensive crisis was reported. There was no relationship between the method of FNA/type of needle used and occurrence of complications. Based on the recollection of these 65 radiologists, who performed approximately 200 FNA of adrenal lesions, a death rate of approximately 1% was estimated.

Conclusions and Clinical Importance

Percutaneous US‐guided FNA of adrenal lesions can be considered a minimally risky procedure, despite the negative perception by radiologists.

Anaesthetic management and complications of canine adrenalectomies: 41 cases (2007-2017)

Little information is available about the management of adrenalectomies in veterinary anaesthesia. The aim of this study was to describe the anaesthetic techniques, the complication rate and outcome of these cases. Data were collected retrospectively from patients' records. Descriptive statistics were performed with Student's t-tests and Chi-square tests where appropriate. Forty-one cases were included. The mean age was 124.7 ± 29.4 months and the median body weight was 23.1 kg (5.3-69 kg). Carcinoma was the most common diagnosis (34.1%). Premedication was most commonly achieved with methadone alone (70.7%) IV. Propofol was the most common induction agent (39%). An infusion of opioids (80.4%) and an epidural injection of morphine (70.7%) were the most common analgesic techniques. Hypotension was the most common complication observed (51.2%). The mortality rate was 14.6%. The lowest recorded oesophageal temperature was statistically associated with the incidence of haemorrhage (P = 0.025). The invasion of the vena cava (P = 0.001) was significantly associated with haemorrhagic complications. The survival rate was better when patients received hydrocortisone intra-operatively (P = 0.026). This study highlights some possible association between the anaesthetic management and the outcome of the procedure.

Perioperative morbidity and mortality in dogs with invasive adrenal neoplasms treated by adrenalectomy and cavotomy

OBJECTIVE

To report the morbidity and mortality associated with adrenalectomy with cavotomy for resection of invasive adrenal neoplasms in dogs and evaluate risk factors for perioperative outcomes.

STUDY DESIGN

Retrospective study.

ANIMALS

Forty-five client-owned dogs.

METHODS

Dogs that underwent open adrenalectomy with cavotomy for resection of adrenal masses with tumor thrombus extending into the vena cava were included. Clinicopathologic data were harvested from medical records. Selected clinical, imaging, and operative variables were statistically evaluated as risk factors for packed red blood cell transfusion, nephrectomy, perioperative death, and overall survival.

RESULTS

Thirty-six of 45 masses were pheochromocytomas, 7 were adrenocortical carcinomas, and 2 were unknown type. Caval thrombus terminated prehepatically in 21 of 45 dogs and extended beyond the porta hepatis but terminated prediaphragmatically (intrahepatic prediaphragmatic location) in 15 dogs and thrombi extended postdiaphragmatically in 5 dogs. Thirty-four (76%) dogs were discharged from the hospital, and 11 (24%) dogs died or were euthanized prior to discharge. Median overall survival time for all 45 dogs was 547 days (95%CI 146-710). Bodyweight, tumor type, and size and extent of caval thrombus did not affect survival to discharge, but postdiaphragmatic (rather than prediaphragmatic) thrombus termination was associated with a greater risk of death.

CONCLUSION

Long-term survival was common in dogs that survived the perioperative period. Postdiaphragmatic thrombus extension affected the prognosis for overall survival.

CLINICAL SIGNIFICANCE

Findings of this study help to stratify operative risk in dogs with adrenal neoplasia and caval invasion.

Use of Minimally Invasive Surgery in the Diagnosis and Treatment of Cancer in Dogs and Cats

Surgical management of neoplastic disease is common in veterinary medicine. Minimally invasive surgery (MIS) has gained widespread acceptance by veterinary surgeons and is experiencing rapid growth and frequency of use. Many neoplastic diseases in the abdomen and thorax of dogs and cats can be treated as effectively with MIS as with traditional open surgery. Additionally, MIS allows for less invasive options for organ biopsy in cancer patients either for initial diagnosis or for staging to inform prognosis and treatment. Despite the recent increase in MIS, additional research is required to further characterize the benefits to oncology patients and to ensure that surgical oncologic principles and patient outcomes are not compromised by the use of MIS.

Pheochromocytoma in Dogs Undergoing Adrenalectomy

Pheochromocytoma is frequent in dogs and carries a guarded prognosis. Current histological criteria may not predict malignant behavior in dogs, similar to humans. In humans, characterization of tumors has been refined using the pheochromocytoma of the adrenal gland scaled score (PASS) and by immunohistochemistry. The study aim was to investigate PASS and immunohistochemical markers used in humans in 24 dogs with pheochromocytoma that underwent adrenalectomy. Dogs with pheochromocytomas were reviewed and tumors collected. Histological sections were evaluated to apply the PASS and were single-labeled for chromogranin A, Ki-67, COX-2, p53, BCL-2, c-erbB-2, vascular endothelial growth factor, and S100. Survival, age, and vascular and capsular invasion were compared for PASS and immunohistochemical markers; results of PASS were also compared for each marker. Associations between markers were tested. PASS and immunohistochemical markers did not differ for survival, age, and vascular and capsular invasion. Tumors showing BCL-2 expression in >50% cells had lower PASS than those with lower expression (PASS: 7 ± 2 vs 9 ± 2; P = .011). Tumors positive for S100 had higher PASS than those that were negative (PASS: 10 ± 2 vs 7 ± 2; P = .001). Results of the different markers were not associated. In conclusion, in the context of canine pheochromocytoma, PASS and the selected immunohistochemical markers are not associated with survival, age, or vascular or capsular invasion. The higher PASS in S100-positive tumors may indicate that pheochromocytomas developing morphologic changes acquire S100 expression. The significance of lower PASS in tumors with elevated BCL-2 expression is uncertain. Overall, the use of PASS and the present immunohistochemical markers may not be useful in dogs with pheochromocytoma.

Concurrent pituitary and adrenocortical lesions on computed tomography imaging in dogs with spontaneous hypercortisolism

Background

Spontaneous hypercortisolism or Cushing's syndrome in dogs is either pituitary or adrenal dependent, but concurrent pituitary and adrenal hypercortisolism also has been reported.

Objective

To determine how often concurrent pituitary and adrenal lesions are present in dogs with spontaneous hypercortisolism.

Animals

Two hundred one client‐owned dogs with spontaneous hypercortisolism.

Methods

Retrospective study. Pre‐ and post‐contrast computed tomography (CT) scans of the pituitary and adrenal glands were performed in dogs with confirmed hypercortisolism.

Results

In dogs with dexamethasone‐suppressible hypercortisolism (122/201), 78 dogs (64%) had an enlarged pituitary gland (median pituitary height/brain area [P/B], 0.43 × 10⁻² mm⁻¹; range, 0.32‐1.21 × 10⁻² mm⁻¹). Two of these 78 dogs had concurrent adrenal lesions. In the remaining dogs (44/122; 36%), the pituitary gland was not enlarged. In the dexamethasone‐resistant group (79/201), the pituitary gland was enlarged in 47 dogs (59%; median P/B, 0.57 × 10⁻²; range, 0.32‐1.50 × 10⁻² mm⁻¹). Eight of these 47 dogs (17%) had concurrent adrenal lesions. In the remaining 32 dexamethasone‐resistant dogs (41%), the pituitary gland was not enlarged. Among them, 27 dogs had adrenal lesions and suppressed ACTH concentrations consistent with adrenal‐dependent hypercortisolism and 5 dogs were diagnosed with pituitary‐dependent hypercortisolism.

Conclusions and Clinical Importance

Concurrent pituitary and adrenal lesions were present in 5% of all dogs with hypercortisolism and in 10% of the dexamethasone‐resistant dogs. Diagnostic imaging of both pituitary and adrenal glands should be included in the diagnostic evaluation of every dog with spontaneous hypercortisolism to obtain information needed for estimation of prognosis and choosing the optimal treatment.

Canine hyperadrenocorticism associations with signalment, selected comorbidities and mortality within North American veterinary teaching hospitals

OBJECTIVE

To describe a large population of dogs with a diagnosis of hyperadrenocorticism at the time of death in North American veterinary teaching hospitals, and to identify comorbid conditions associated with hyperadrenocorticism.

MATERIALS AND METHODS

Retrospective cohort study of 1519 dogs with hyperadrenocorticism from a population of 70,574 dogs reported to the Veterinary Medical Database. Signalment, presence or absence of hyperadrenocorticism, aetiology of hyperadrenocorticism (if described), frequency of select comorbidities and causes of death were evaluated in dogs with and without hyperadrenocorticism.

RESULTS

Hyperadrenocorticism was more frequent in females. Neutering was associated with a minor, but significant, increase in the odds of hyperadrenocorticism. Hyperadrenocorticism was the presumed cause of death of 393 (25∙9%) of affected dogs. When aetiology was specified (527 dogs, corresponding to 34∙7% of the cases), pituitary-dependent hyperadrenocorticism [387 (73∙4%) out of 527 dogs] was more common than functional adrenocortical tumour [136 (25∙8%) out of 527 dogs). Hyperadrenocorticism was over-represented in certain expected (miniature poodle, dachshund) and unexpected (Irish setter, bassett hound) breeds compared with the population at large. Of the select comorbidities investigated, dogs with hyperadrenocorticism were at increased risk for concurrent diabetes mellitus, urinary tract infection, urolithiasis, hypertension, gall bladder mucocoele and thromboembolic disease compared with dogs without hyperadrenocorticism.

CLINICAL SIGNIFICANCE

Hyperadrenocorticism is significantly associated with certain comorbid conditions but is not a major cause of mortality in affected dogs. Documented patterns now provide targets for prospective clinical research.

ACVIM consensus statement: Guidelines for the identification, evaluation, and management of systemic hypertension in dogs and cats

An update to the 2007 American College of Veterinary Internal Medicine (ACVIM) consensus statement on the identification, evaluation, and management of systemic hypertension in dogs and cats was presented at the 2017 ACVIM Forum in National Harbor, MD. The updated consensus statement is presented here. The consensus statement aims to provide guidance on appropriate diagnosis and treatment of hypertension in dogs and cats.

Treating canine Cushing's syndrome: Current options and future prospects

Naturally occurring hypercortisolism, also known as Cushing's syndrome, is a common endocrine disorder in dogs that can be caused by an adenocorticotrophic hormone (ACTH)-producing pituitary adenoma (pituitary-dependent hypercortisolism, PDH; 80-85% of cases), or by an adrenocortical tumor (ACT; 15-20% of cases). To determine the optimal treatment strategy, differentiating between these two main causes is essential. Good treatment options are surgical removal of the causal tumor, i.e. hypophysectomy for PDH and adrenalectomy for an ACT, or radiotherapy in cases with PDH. Because these options are not without risks, not widely available and not suitable for every patient, pharmacotherapy is often used. In cases with PDH, the steroidogenesis inhibitor trilostane is most often used. In cases with an ACT, either trilostane or the adrenocorticolytic drug mitotane can be used. Although mostly effective, both treatments have disadvantages. This review discusses the current treatment options for canine hypercortisolism, and considers their mechanism of action, efficacy, adverse effects, and effect on survival. In addition, developments in both adrenal-targeting and pituitary-targeting drugs that have the potential to become future treatment options are discussed, as a more selective and preferably also tumor-targeted approach could have many advantages for both PDH and ACTs.

Retrospective evaluation of toceranib phosphate (Palladia®) use in the treatment of inoperable, metastatic, or recurrent canine pheochromocytomas: 5 dogs (2014-2017)

BACKGROUND

Effective treatment options for inoperable, metastatic, or recurrent canine pheochromocytomas are lacking. In humans, specific germline mutations exist that drive the development of pheochromocytomas. Pharmaceutical blockade of these abnormalities with small molecule inhibitors are an effective treatment strategy. Similar mutations may exist in the dog, and thus, treatment with similar small molecule inhibitors may provide a survival advantage. The purpose of this study was to assess the role of toceranib phosphate in the treatment of inoperable, metastatic, or recurrent canine pheochromocytomas.

RESULTS

Retrospectively, medical records of dogs that had a diagnosis or suspect diagnosis of a pheochromocytoma were reviewed for information regarding response to toceranib phosphate and overall outcome. Five dogs were identified that fit the inclusion criteria. All five experienced clinical benefit (1 partial response, 4 stable disease). Progression-free interval (PFI) for the dog with the partial response was 61 weeks. PFI for the two dogs with stable measurable disease were 36 weeks and 28 weeks. PFI in the two dogs with stable metastatic disease were at least 11 weeks and 18 weeks.

CONCLUSIONS

Based on this limited series of dogs, the results suggest that toceranib may have biological activity in dogs with primary and metastatic pheochromocytomas. Larger studies are needed to define the use and response to toceranib in dogs with gross, microscopic, and metastatic pheochromocytoma.

Prevalence of adrenal gland masses as incidental findings during abdominal computed tomography in dogs: 270 cases (2013-2014)

OBJECTIVE To determine the prevalence and clinical characteristics of incidental adrenal gland masses identified in dogs undergoing abdominal CT. DESIGN Retrospective case series. ANIMALS 270 client-owned dogs. PROCEDURES Medical records of dogs that underwent abdominal CT from June 2013 through June 2014 were reviewed. Patients were excluded if they had undergone CT because of a history or clinical signs of an adrenal gland mass or disease. Information collected included history, signalment, initial complaint, serum alkaline phosphatase activity, urine specific gravity, and whether abdominal ultrasonography was performed. Imaging reports generated by the board-certified radiologist who evaluated the CT images were reviewed. RESULTS Incidental adrenal gland masses were detected in 25 of the 270 (9.3%) dogs. Dogs with incidental adrenal gland masses were significantly older (median, 12.0 years; range, 8.0 to 15.0 years) than dogs without (8.2 years; range, 0.1 to 13.1 years). Dogs examined for neoplasia were significantly more likely to have an incidental adrenal gland mass (22/138 [15.9%]) than were dogs examined for any other reason (3/132 [2.3%]), but these dogs were also significantly older. No other risk factors were identified. Histologic examination was performed in only 3 of the 25 dogs with incidental adrenal gland masses; 2 had cortical adenomas and 1 had a pheochromocytoma and cortical adenoma. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that a clinically important percentage of dogs undergoing abdominal CT will have incidental adrenal gland masses, with incidental masses more likely in older than in younger dogs.

Repetitive ultrasonographic assessment of adrenal size and shape changes: a clue for an asymptomatic sex hormone-secreting adenoma

Diagnosis of an adrenal tumor without typical clinical signs related to hyperadrenocorticism and elevated alkaline phosphatase is challenging. This report describes a sex hormone-secreting adrenal tumor in a 10-year-old castrated male Shih Tzu evaluated through repetitive ultrasonographic examination. An adrenocorticotropic hormone stimulation test revealed elevated concentrations of androstenedione and 17-hydroxyprogesterone but a normal cortisol concentration. A mass was surgically excised and adenoma was diagnosed histopathologically. In the present case, adrenal tumor was strongly suspected based on a gradual increase in adrenal size and a change from peanut shape to an irregular mass on repetitive ultrasonography. Repetitive ultrasonographic examination of the adrenal gland is recommended when an abnormal ultrasonographic appearance of adrenal gland is identified, even in an asymptomatic dog.

Paradoxical bradycardia during surgical caudal vena cava occlusion in an anesthetized dog

OBJECTIVE

To describe the anesthetic management of a dog undergoing caudal vena cava (CVC) occlusion during adrenalectomy, and to discuss a reflex bradycardia that was observed during the procedure.

CASE SUMMARY

General anesthesia of a 10-year-old Rhodesian ridgeback for excision of an adrenal mass and associated CVC tumor thrombus was performed. The dog was premedicated with IV methadone and anesthesia was induced with IV alfaxalone and maintained with isoflurane in 100% oxygen. An IV remifentanil infusion was administered for intraoperative analgesia. Surgical removal of the thrombus necessitated temporary complete occlusion of the CVC. During CVC occlusion an acute paradoxical bradycardia occurred, which was successfully treated with IV atropine. The cardiovascular change resembled a Bezold-Jarisch or reverse Bainbridge reflex, and was believed to be mediated by cardiac mechanoreceptors following the sudden decrease in preload. Increased myocardial contractility subsequent to increased sympathetic nervous system activity may also have contributed. A decrease in urine output was observed following CVC occlusion but had returned to normal 2 hours following the end of anesthesia. Recovery from anesthesia was otherwise uneventful.

NEW OR UNIQUE INFORMATION PROVIDED

Although the mechanism is unclear, a paradoxical bradycardia may occur during complete CVC occlusion in the dog. Factors that increase sympathetic nervous system outflow, such as administration of dopamine, may have contributed to the occurrence of the reflex.

Collateral circulation in ferrets (Mustela putorius) during temporary occlusion of the caudal vena cava

OBJECTIVE To determine whether extent of collateral circulation would change during temporary occlusion of the caudal vena cava (CVC) in ferrets (Mustela putorius), a pressure change would occur caudal to the occlusion, and differences would exist between the sexes with respect to those changes. ANIMALS 8 adult ferrets (4 castrated males and 4 spayed females). PROCEDURES Ferrets were anesthetized. A balloon occlusion catheter was introduced through a jugular vein, passed into the CVC by use of fluoroscopy, positioned cranial to the right renal vein, and inflated for 20 minutes. Venography was performed 5 and 15 minutes after occlusion. Pressure in the CVC caudal to the occlusion was measured continuously. A CBC, plasma biochemical analysis, and urinalysis were performed immediately after the procedure and 2 or 3 days later. RESULTS All 8 ferrets survived the procedure; no differences were apparent between the sexes. Vessels providing collateral circulation were identified in all ferrets, indicating blood flow to the paravertebral venous plexus. Complications observed prior to occlusion included atrial and ventricular premature contractions. Complications after occlusion included bradycardia, seizures, and extravasation of contrast medium. Mean baseline CVC pressure was 5.4 cm H2O. During occlusion, 6 ferrets had a moderate increase in CVC pressure (mean, 24.3 cm H2O) and 2 ferrets had a marked increase in CVC pressure to > 55.0 cm H2O. CONCLUSIONS AND CLINICAL RELEVANCE Caval occlusion for 20 minutes was performed in healthy ferrets with minimal adverse effects noted within the follow-up period and no apparent differences between sexes. The CVC pressure during occlusion may be prognostic in ferrets undergoing surgical ligation of the CVC, which commonly occurs during adrenal tumor resection.

Anaesthetic management of a unilateral adrenalectomy of an adrenocortical tumour in a dog

Adrenalectomies in dogs are being more commonly performed, however anaesthetic management of such cases can be challenging due to the multiple aetiologies of adrenal tumours and the physiological role of adrenal glands. This case report describes the anaesthetic management of a dog with clinical signs of hyperadrenocorticism that underwent unilateral adrenalectomy via laparotomy and discusses anaesthetic preparedness, protocol selection and management of complications for dogs undergoing adrenalectomy.

Preoperative Differential Diagnosis of Canine Adrenal Tumors Using Triple-Phase Helical Computed Tomography

OBJECTIVE

To characterize the computed tomography (CT) findings for canine adrenal tumors, including cortical adenoma, cortical adenocarcinoma, and pheochromocytoma, and to evaluate the feasibility and usefulness of preoperative triple-phase helical CT for differentiation of tumor types and surgical planning.

STUDY DESIGN

Retrospective study.

ANIMALS

Dogs with adrenal tumors (n=36).

METHODS

All dogs underwent triple-phase helical CT, followed by adrenalectomy and histopathological diagnosis of the resected mass. Precontrast images, arterial, venous, and delayed phase images were obtained. In all cases, morphological characteristics and CT values and calculations, including the percentage enhancement washout ratio, relative percentage washout, enhancement washin, and enhancement washout, were analyzed and compared among the tumor types.

RESULTS

Of the 36 dogs with adrenal masses, cortical adenocarcinoma was most commonly diagnosed (16 dogs), followed by pheochromocytoma (13 dogs), and cortical adenoma (7 dogs). The precontrast minimum CT value and enhancement washout between venous and delayed phases in the cortical adenoma were significantly higher than those in the cortical adenocarcinoma. The maximum CT values of the precontrast image and arterial and venous phases, the enhancement washin and washouts, percentage enhancement washout ratio, and relative percentage washout in the pheochromocytomas were significantly higher than those in cortical adenocarcinoma.

CONCLUSION

The differential diagnosis of canine adrenal tumors was feasible based on triple-phase CT findings, including morphological features, CT values, and intratumoral contrast attenuation. Preoperative diagnosis using triple-phase helical CT may be useful for surgical planning in dogs with adrenal tumors.

Clinical findings, diagnostics and outcome in 33 cats with adrenal neoplasia (2002-2013)

OBJECTIVES

The objective of this retrospective study was to describe the clinical signs and diagnostic findings in cats with histopathologically confirmed adrenal neoplasms, and to assess correlations with survival data.

METHODS

Study data were acquired by reviewing medical records for all cats diagnosed with adrenal neoplasms at seven referral institutions between 2002 and 2013. Inclusion criteria required a histopathologic diagnosis of an adrenal neoplasm (ante-mortem or on necropsy).

RESULTS

Thirty-three cats met the inclusion criteria for the study. The most common presenting complaints included weakness (n = 12), respiratory signs (n = 4), blindness (n = 4) or gastrointestinal signs (n = 3). Laboratory abnormalities included hypokalemia (n = 18), alkalemia (n = 12), elevated creatine kinase (>3000, n = 5) and azotemia (n = 4). In addition, hypertension was noted in 13 cats. Thirty cats were diagnosed with cortical tumors (17 carcinomas, 13 adenomas) and three cats were diagnosed with pheochromocytomas. Twenty-five cats underwent tests to evaluate the function of the adrenal tumors; 19/25 cats had functional tumors (hyperaldosteronism [n = 16], hypercortisolemia [n = 1], high estradiol [n = 1], and hypersecretion of aldosterone, estradiol and progesterone [n = 1]). Twenty-six cats underwent adrenalectomy, one cat was medically managed and six were euthanized without treatment. Long-term survival postoperatively ranged from 4-540 weeks, with 20 (77%) cats surviving the perioperative period of 2 weeks. The only variable that was found to be negatively associated with survival was female sex. The most common complications noted during the perioperative period were hemorrhage and progressive lethargy and anorexia.

CONCLUSIONS AND RELEVANCE

Surgical treatment for feline adrenal tumors (regardless of tumor type) resulted in good long-term survival. Given that pre- and postoperative hypocortisolemia was identified in this study, and, in addition, hypersecretion of more than one adrenal hormone occurred in one cat, adrenal panels prior to surgery may be beneficial as part of the preoperative work-up.

Adrenocortical tumor in a cat secreting more than one type of corticosteroid

CASE SUMMARY

A 14-year-old, spayed female domestic shorthair cat was evaluated because of a right adrenal mass. The referring veterinarian had started treatment for hypokalemia and systemic arterial hypertension. During the initial evaluation the cat was alert and responsive, and serum potassium concentration was within the reference range. Serum concentrations of aldosterone and progesterone were increased. Atrophy of the contralateral adrenal and an exaggerated response of cortisol to stimulation with adrenocorticotropic hormone suggested hypersecretion of cortisol. Unilateral adrenalectomy was performed and recovery was uneventful. Histologic examination of the mass revealed an adrenocortical tumor. After surgery, clinical signs of hypercortisolism, hyperaldosteronism and hyperprogesteronism were no longer observed, and neither potassium supplementation nor antihypertensive treatment were needed.

RELEVANCE AND NOVEL INFORMATION

In cases with an adrenocortical tumor, clinicians should investigate whether the tumor hypersecretes glucocorticoids, mineralocorticoids, sex steroids or combinations of these. Hypersecretion of more than one adrenal hormone may occur in a cat with an adrenocortical tumor.