Primary and Secondary Heart Tumours in Dogs and Cats

Cardiac embryonal rhabdomyosarcoma in a domestic shorthair cat

Rhabdomyosarcomas (RBMs) are rare neoplasms arising from striated muscle tissues in domestic animals and are exceptionally uncommon, affecting the heart of domestic cats. A case of cardiac embryonal RBM was detected in a two-year-old female domestic shorthair cat. The cat exhibited dyspnea, anorexia, pericardial and pleural effusions, ultimately succumbing to severe respiratory arrest. Gross post-mortem examination revealed a firm yellow-tan mass measuring 2.5 × 1.5 cm protruding from the right atrium, along with metastatic nodules of various sizes dispersed throughout the liver, spleen, and lungs. On histology, the right atrium exhibited a highly cellular infiltrative and vascularized mass predominantly composed of spindle and small round cells arranged in dense cellular bundles supported by a scant fibrous stroma interspersed with scarce regions of loosely myxoid stroma. Comparable histological features were noted in the metastatic lesions. Immunohistochemical analysis revealed positive immunolabeling for vimentin, desmin, MyoD1, and fast myosin, while no immunostaining was observed for smooth muscle actin, chromogranin, and S100. Histological and immunohistochemical features supported the diagnosis of metastatic cardiac embryonal RBM spindle cell variant in the cat. Cardiac embryonal RBMs should be included in the differential diagnosis of cardiac and thoracic neoplasms in domestic cats presenting with clinical signs indicative of cardiac arrest or sudden death.

Case report: Diffuse large B-cell lymphoma presenting as congestive heart failure in a cat

Cardiac lymphoma is uncommon in cats and is rarely considered as a differential diagnosis for congestive heart failure. A 10-year-old neutered male domestic short-haired cat with clinical histories of feline immunodeficiency virus, diabetes mellitus, and congestive heart failure was humanely euthanized. Post-mortem evaluation demonstrated a massively infiltrative round cell neoplasm of the heart, resulting in CHF. Immunohistochemistry of neoplastic tissue was consistent with diffuse large B-cell lymphoma. This case demonstrates a peculiar presentation of cardiac diffuse large B-cell lymphoma, with chronic feline lentiviral infection possibly contributing to disease initiation and progression.

Computed tomographic findings in canine and feline heart base tumors (25 cases)

Tumors located at the heart base are rare in dogs and cats and aortic body tumors (chemodectoma/paraganglioma), hemangiosarcoma, ectopic thyroid carcinoma, lymphoma, and other uncommon neoplasia can be found at that location. The objective of this retrospective case series was to describe the CT characteristics of canine and feline heart base tumors. CT studies of 21 dogs and four cats with histologically or cytologically confirmed heart base tumors were reviewed for size, location, shape, margination, contrast enhancement, adjacent neovascularization, invasion, mass effect, cavitary effusions, and metastasis. Neuroendocrine tumors (15 aortic body tumors, three ectopic thyroid carcinoma, and three nonspecific neuroendocrine) were more commonly observed than hemangiosarcoma (4) and were frequently located between the cranial vena cava and aortic arch (12/21; 57%) and or dorsal to the pulmonary trunk bifurcation/pulmonary arteries (10/21; 48%). Hemangiosarcoma was more commonly found cranioventral to the aortic arch and cranial to the right auricular appendage (3/4; 75%). Mediastinal and peritumoral neovascularization was associated with 16/21 (76%) neuroendocrine tumors but none of the hemangiosarcoma. Median postcontrast attenuation in Hounsfield units (HU) was higher in neuroendocrine (110 HU) than in hemangiosarcoma (51 HU). Pericardial effusion was frequently observed with hemangiosarcoma (3/4; 75%) and infrequently in neuroendocrine (3/21; 14%). In four cases (all neuroendocrine), concurrent cranial mediastinal masses were present. CT provides useful information regarding the characteristics of heart base tumors, indicating differences between the appearance of neuroendocrine tumors and hemangiosarcoma. However, no differences were found between aortic body tumors and ectopic thyroid carcinoma.

Ultrasound, Histomorphologic, and Immunohistochemical Analysis of a Cardiac Tumor with Increased Purkinje Cells Detected in a Canine Fetus 42 Days into Pregnancy

A seven-year-old healthy female Chow Chow was referred for pregnancy monitoring. Ultrasonography was used to evaluate all pregnancy and fetus parameters, and they were found to be normal. During the examination of the 42 day pregnant bitch, an unusual mass was seen in a fetus's heart. This fetus had a cardiac frequency of 273-300 beats, while the others had heart rates of 220-240 beats. Natural vaginal birth occurred at 63 days pregnant: the first two puppies were stillborn but perfectly formed, and the other three were alive and had optimal APGAR. In one of two deceased puppies, an unusual, reddish, smooth mass occupying the space in the heart was found through necroscopy. The organ was submitted for histological examination. Histopathology, immunohistochemical, and histochemical analyses all indicated a cardiac tumor with increased Purkinje cells. This type of tumor has been described in infants, swine, bearded seals, and deer but never in fetuses and neonates of dogs. To our knowledge, this is the first such case reported in veterinary medicine.

Assessment of left and right ventricular systolic function in dogs with multicentric lymphoma

OBJECTIVE

Myocardial dysfunction in cardio-oncology is generally thought to be related to the cardiotoxicity of chemotherapy treatment. However, it is known that some tumors have direct effects on myocardial function. These effects have already been studied in man, but there are no publications of these of the effects in dogs. Novel advanced echocardiographic techniques may allow early detection of myocardial dysfunction when compared to conventional echocardiographic techniques. This study aims to assess myocardial systolic function in dogs with multicentric lymphoma prior to initiation of chemotherapy.

ANIMALS

Fifteen dogs with multicentric lymphoma and nineteen healthy dogs.

METHODS

Case-control study. Dogs with multicentric lymphoma and healthy control dogs underwent physical examination, electrocardiography, systolic blood pressure measurement, standard and speckle tracking echocardiography to assess biventricular systolic function.

RESULTS

There were no differences between groups in terms of ejection fraction, fractional shortening, left ventricular systolic and diastolic diameter, tricuspid annular plane systolic excursion, mitral annular plane systolic excursion and fractional area change of the right ventricle (RV). However, there was a reduction in the values of global circumferential strain (p = 0.0003), RV strain (p = 0.01) and RV tissue motion annular displacement (p < 0.05) in the dogs with lymphoma when compared to the control group.

CONCLUSIONS

Speckle tracking techniques appear to demonstrate early systolic dysfunction, primarily affecting the RV, in dogs with lymphoma prior to chemotherapy treatment.

Pathological features of primary cardiac myxoid tumour in dogs: a review of 11 cases (2002-2022)

This report documents the pathological features of primary cardiac myxoid tumour (MT) in 11 dogs. Macroscopically, all the tumours were located in the tricuspid valve (TV), its septal leaflet being predominantly affected. Therefore, it appears that the TV is the most common site of occurrence for cardiac MT in dogs. Two gross anatomical types of canine valvular MT were evident. Seven of the 11 tumours were round or oval with a smooth or gently lobulated and glistening surface, while the other four were gelatinous, multilobulated and polypoid, with an irregular surface. Microscopically, in nine cases the tumours had an abundant myxoid matrix within which elongated spindle-shaped cells with no remarkable cytological atypia were sparsely embedded, suggesting a benign character (ie, myxoma). In the other two cases the tumours consisted of variably dense, haphazardly arranged, interlacing streams of anaplastic spindle-shaped or polygonal cells containing many mitotic figures, indicative of a malignant form of myxoma (ie, myxosarcoma). Isolated or clustered collections of myxoma cells (eg, cords, rings, syncytia) characteristic of human atrial myxoma were only rarely evident or lacking in all 11 cases, indicating that rarity or absence of such structural features may be specific to valvular MTs. Immunohistochemical findings were indicative of smooth muscle differentiation of the neoplastic cells. Tumour embolization to the intrapulmonary arteries and/or tumour implantation on the endocardium of the right heart chambers was evident only in the four cases of irregular-surfaced MT.

A primary multiple pleomorphic rhabdomyosarcoma of the heart in an adult dog

BACKGROUND

Heart tumors are rare in dogs. They can be benign or malignant. Clinical signs depend primarily on the location of the tumor and its effect on blood flow.

CASE PRESENTATION

An eleven-year-old crossbreed male dog lethargic and anorectic for previous 3 days was presented to the veterinary clinic. The focused ultrasound assessment with sonograms in trauma (FAST) revealed multiple tumors in the heart which were then confirmed in echocardiographic examination performed by a veterinary cardiologist. Due to the poor general condition and grave prognosis, the dog was humanely euthanized. The autopsy revealed numerous intracardiac tumors in all four heart chambers. No proliferative changes were found in other organs either in thoracic or abdominal cavity. Immunohistochemical examination was performed using formalin-fixed, paraffin-embedded tissue from heart masses. The antibodies against myoglobin, desmin, smooth muscle actin, vimentin, CD34, S100, and pan-cytokeratin (AE1/AE3) were used. Microscopically, the tumor was composed of fascicles of spindle-shaped cells with pale eosinophilic cytoplasm with round, oval, and focally elongated nuclei and one or two prominent nucleoli. The tumor cells showed strong diffuse cytoplasmic immunopositivity for myoglobin and vimentin and focal staining for desmin. Immunostainings for smooth muscle actin-SMA, CD34, pan-cytokeratin, S-100 protein were negative. The immunohistochemical staining pattern confirmed rhabdomyosarcoma.

CONCLUSIONS

This is the first description of the primary multiple heart rhabdomyosarcoma in a dog.

Case report: Malignant chemodectoma with hepatic metastasis in a cat

A 10-year-old, male-neutered, domestic short-hair cat was examined at the Veterinary Health Center Emergency Service at Kansas State University for a one-day history of dyspnea. Prior to thoracocentesis, sedation was provided. The cat stopped breathing after sedation and went into cardiac arrest. Cardiopulmonary resuscitation (CPR) was unsuccessful. At necropsy, there was severe pleural effusion and bilateral pulmonary atelectasis. The myocardium of the atria and ventricles, and tunica adventitia of coronary vessels, pulmonary artery, and aorta, had pale, firm, multinodular masses ranging from 0.3 to 0.5 cm in diameter. Multiple nodules were also present in the liver. Multifocally expanding the epicardial fat and compressing the underlying epicardium, infiltrating, and expanding the myocardium, and expanding the walls of major vessels, there was a multinodular, unencapsulated, densely cellular neoplasm composed of polygonal epithelial cells arranged in nests and packets and supported by a fine fibrovascular stroma. The nodules in the liver had similar histologic features. In this case, neoplastic cells at the primary and metastatic sites were intensely immunoreactive to synaptophysin, variably reactive to chromogranin A, and negative for neuron specific enolase, cytokeratin, vimentin, thyroglobulin, and smooth muscle actin. The gross, histologic, and immunohistochemical findings support the diagnosis of chemodectoma, with metastases to the liver. Synaptophysin and chromogranin A were the most useful immunohistochemical markers to diagnose malignant chemodectoma in this cat.

Transvalvular Pulmonary Stent Angioplasty for Management of an Intraluminal, Compressive Chemodectoma in a Dog

•Chemodectomas are a common type of heart-base mass in dogs •Chemodectomas may cause compression or invasion of adjacent structures •Vascular stent placement may improve blood flow across a vascular obstruction

Pericardial effusion secondary to epicardial undifferentiated pleomorphic sarcoma in a young cat

Case summary

A 6.4 kg 3-year-old male neutered indoor-outdoor domestic shorthair cat was referred for further evaluation of non-resolving lethargy and hyporexia of 4 days' duration. Physical examination identified tachypnea with mild respiratory effort and muffled lung sounds bilaterally. Point-of-care ultrasound revealed a large volume of pleural and pericardial effusion (PCE), which was confirmed by thoracic radiography. Echocardiogram indicated normal cardiac function but revealed a mass-like structure along the left epicardium within the pericardial space. After 72 hours in hospital, re-evaluation via echocardiogram showed the epicardial mass lesion to have doubled in size and with apparent extension to involve the pericardium. The patient was hospitalized for 72 h of supportive care and intervention, including therapeutic pericardiocentesis, bilateral thoracocentesis, thoracic and cardiac imaging and infectious disease testing. On the third day of hospitalization, the patient developed cardiac tamponade. Further workup was discussed, including CT and subtotal pericardiectomy with biopsy, but the cat was euthanized due to clinical decline and rapid re-accumulation of effusion. Post-mortem histopathologic evaluation diagnosed an epicardial pleomorphic sarcoma, exclusive of mesothelioma or histiocytic sarcoma on immunohistochemistry (IHC).

Relevance and novel information

This report describes a case of epicardial undifferentiated pleomorphic sarcoma (UPS) in a young cat presenting with pleural and PCE. Pleomorphic sarcoma is a rarely reported mesenchymal neoplasia in the feline patient and has thus far primarily been identified in peripheral soft tissue structures. IHC is key to the correct histopathologic diagnosis. To our knowledge, epicardial UPS has not been previously reported in a cat.

Unusual diagnosis of feline cardiac lymphoma using cardiac needle biopsy

Background

Cardiac tumors in cats are relatively rare, with lymphoma accounting for more than half of all cases. However, feline cardiac lymphoma is often diagnosed post-mortem, and it is difficult to diagnose while the cat is still alive. It is the first report of a direct, rather than estimative, diagnosis with cardiac needle biopsy of a living cat with cardiac lymphoma.

Case presentation

A 3-year-old domestic short-haired male cat experienced loss of energy and loss of appetite. Thoracic radiography and transthoracic echocardiography showed cardiomegaly with slight pleural effusion and cardiac tamponade due to pericardial effusion, respectively. In addition, partial hyperechoic and hypertrophy of the papillary muscle and myocardium were observed. Blood test showed an increase in cardiac troponin I levels. Pericardial fluid, removed by pericardiocentesis, was analyzed; however, the cause could not be determined. With the owner’s consent, pericardiectomy performed under thoracotomy revealed a discolored myocardium. Cardiac needle biopsy was performed with a 25G needle, and a large number of large atypical lymphocytes were collected; therefore, a direct diagnosis of cardiac lymphoma was made. Pathological examination of the pericardium diagnosed at a later date revealed T-cell large cell lymphoma. The cat underwent chemotherapy followed by temporary remission but died 60 days after the diagnosis. Postmortem, two-dimensional speckle-tracking echocardiography (data when alive) revealed an abnormal left ventricular myocardial deformation, which corresponded to the site of cardiac needle biopsy.

Conclusions

This rare case demonstrates that cardiac lymphoma should be added to the differential diagnosis in cats with myocardial hypertrophy and that the diagnosis can be made directly by thoracotomy and cardiac needle biopsy. In addition, the measurement of cardiac troponin I levels and local deformation analysis of the myocardium by two-dimensional speckle-tracking echocardiography may be useful in the diagnosis of cardiac tumors.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-022-03357-7.

Histopathological Findings in the Cardiovascular System of Psittacidae in Routine Diagnostics

Samples of 363 Psittacidae were included in this study with a focus on cardiovascular diseases. These were identified in 28.9% of the animals, with pericarditis and/or epicarditis and myocarditis representing approximately half of all lesions and bacteria being the most common infectious cause. Cardiac lymphoma was only seen in 5 birds, whereas degenerative vascular lesions were diagnosed in 26.7% of the cases. Histopathology in the context of clinical findings and complementary examination results is the most useful tool for the evaluation of cardiac diseases.

Periarticular histiocytic sarcoma with heart metastasis in a cat

A 4-year-old intact female domestic short-haired cat was referred for recommendations about adjuvant medical treatment 1 month after left forelimb amputation due to periarticular histiocytic sarcoma (HS). At presentation, physical abnormalities were limited to enlarged ipsilateral superficial cervical and axillary lymph nodes. Routine blood analysis, abdominal ultrasound, and thoracic radiology were unremarkable. The cat initially received lomustine without any adverse events. Four weeks later, the cat developed severe acute respiratory distress. Results of thoracic radiographs and transthoracic echocardiographic analysis were suggestive of pulmonary and heart metastasis. Due to the cat's poor clinical condition and prognosis, the owner elected euthanasia, and a necropsy was performed. Based on gross pathology, histopathology, and immunohistochemistry, an HS with nodal, renal, pulmonary, and heart (right auricular and right ventricular) metastases was diagnosed. This case represents the first description of HS with a heart metastasis in a cat, providing further insight into the clinical course and metastatic behavior of this rare malignant neoplasm. Clinicians should be aware of this site of metastasis and consider HS in the list of differential diagnoses for secondary heart tumors in cats.

Ultrasound-Guided Radiofrequency Ablation of Chemodectomas in Five Dogs

Chemodectomas are low prevalence tumors with complex clinical management. Many present as an incidental finding however, in other dogs, they produce pericardial effusion and/or compression, leading to the appearance of severe clinical signs. There are currently several approaches: surgery, radiotherapy, stent placement and chemotherapy. This is the first description of percutaneous echo-guided radiofrequency ablation of aortic body tumors. This minimally invasive treatment is based on high frequency alternating electrical currents from an electrode that produces ionic agitation and generates frictional heat, causing coagulation necrosis. Five dogs with an echocardiographic and cytological diagnosis of chemodectoma underwent percutaneous echo-guided radiofrequency ablation. At the time of presentation, all the dogs showed clinical signs, such as ascites and/or collapse. There were no complications either during the procedure or in the following 24 hours. Rapid clinical improvement associated with a reduction in size and change in sonographic appearance of the mass were achieved with no complications. Six months follow-up was carried out in all dogs. A second percutaneous echo-guided RFA was performed eight months after the first procedure in one dog. Based on our experience, radiofrequency ablation seems to be a feasible and safe technique, making it a potential alternative therapeutic approach in the clinical management of aortic body tumors leading to severe clinical compromise.

Canine and feline haemangiosarcoma

INTRODUCTION

Haemangiosarcoma (HSA) is a malignant neoplasm of dogs and cats that is suspected to originate from a pluripotent bone marrow progenitor with a complex and multifactorial pathogenesis.

APPROACH

Pertinent literature was identified, reviewed, and summarized for inclusion in the manuscript.

RESULTS/INTERPRETATION

Dogs are more frequently diagnosed with HSA than cats, and primary sites of this disease include dermal, subcutaneous/intramuscular, and visceral (most commonly the spleen). Dogs and cats with HSA generally have a poor prognosis owing to the rapid and widespread metastasis typically associated with this disease. However, some forms such as cutaneous HSA behave in a less aggressive fashion with improved outcomes. Surgical excision and anthracycline-based chemotherapy remain the mainstays of treatment, although novel treatment modalities are currently under investigation for potential roles in treatment of this disease.

CONCLUSION

This review aims to describe the clinical presentation and progression of the various forms of HSA in dogs and cats as well as to provide a systematic review of the veterinary literature with a focus on the various published treatment options and associated outcomes.

Long-term outcomes with conventional fractionated and stereotactic radiotherapy for suspected heart-base tumours in dogs

Published radiotherapy results for suspected heart-based tumours in dogs are limited. In this retrospective longitudinal study (3/2014-2019), eight dogs with either clinical signs attributable to a heart-base mass (6), or asymptomatic with a progressively larger mass on echocardiogram (2), received conventional fractionated radiotherapy (CFRT) or stereotactic body radiotherapy (SBRT). Clinical findings in symptomatic cases included one or more of the following: retching/coughing (4), exercise intolerance (2), collapse (1), pericardial effusion (2), rare ventricular premature contractions (2), abdominal effusion (1), or respiratory distress due to chylothorax (1). CFRT cases received 50 Gray (Gy) in 20 fractions and SBRT cases received 30 Gy in 5 or 24 Gy in three fractions. Two dogs received chemotherapy post-radiation. At analysis, 7/8 dogs were deceased and one was alive 684 days post-treatment. The estimated median overall survival (MOS) from first treatment was 785 days (95% CI 114-868 days, [range 114-1492 days]). Five dogs received CFRT (MOS 817 days; (95% CI 155 days-not reached [range 155-1492 days])). Three dogs received SBRT with one alive at analysis (MOS 414 days, (95% CI, 114 days-not reached [range 114-414 days])). No statistically significant difference was found between survival for CFRT and SBRT. Of the symptomatic patients, 5/6 showed improvement. Mass size reduced in 4/5 cases receiving follow-up ultrasounds. Possible complications included asymptomatic radiation pneumonitis (4), atrial tachycardia/premature beats (4) and pericardial effusion with heart failure coincident with tumour progression (1). This study provides preliminary evidence that radiotherapy may impact clinically relevant or progressively enlarging heart-base masses.

The Rare Occurrence of a Left Atrial Thrombus in a Dog

Intracardiac thrombi are rare in dogs. If they occur, they are mostly seen in the right atrium while only two case reports describing a mural left atrial thrombus in dogs are available. This case report describes a 14-year-old mixed-breed bitch that was presented at the clinic because of dyspnoea. The dog suffered from alopecia for about three years and displayed polyuria and polydipsia for a number of months. Clinical examination revealed intensified inspiratory and expiratory respiratory sounds and various heart sounds. Chest X-ray showed cardiomegaly (VHS 11) and a mixed bronchoalveolar lung pattern of the caudal lung. A transthoracic echocardiography was performed and showed a moderate mitral regurgitation, a highly dilated left atrium, a low-grade pulmonary insufficiency, and a minimal aortic and tricuspid insufficiency. Additionally, a free-floating ball thrombus was found in the left atrium. Hyperadrenocorticism was indicated by an ACTH stimulation test. The previous medical therapy of the referring veterinarian consisted of benazepril and furosemide and was complemented by clopidogrel. The pet owners declined any further clinical diagnostics and therapy. The dog died 19 days later. This is the first reported case of a dog with a free-floating left atrial thrombus. Specific therapeutic strategies for intracardiac thrombi in the dog are currently not available, and therefore, every patient should be treated individually.

Mediastinal histoplasmosis with cardiac involvement in a cat

Histoplasmosis is the second most common fungal infection reported among domestic felines in the United States. Dissemination of the organism after inoculation is common and affected organ systems include the respiratory tract, gastrointestinal tract, reticuloendothelial organs, skeletal system, integument, and ocular system. However, histoplasmosis presenting as a discrete granulomatous mass identified on echocardiogram has never been reported in the veterinary literature. Here, we describe the first case of feline histoplasmosis presenting as a granuloma with cardiac involvement. The patient, a 6-year-old male neutered domestic longhair feline, was referred for tachypnea and dyspnea. A mass in the cranial mediastinum abutting the heart was diagnosed via two-dimensional echocardiography. Cytology of fine needle aspirates from the mass revealed round yeast structures consistent with Histoplasma spp. The patient was treated with oral fluconazole therapy, and subsequent rechecks have shown marked improvement in clinical parameters, lesion size, and antigen concentrations.

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.

Successful Treatment of Urinary Bladder Hemangiosarcoma by Partial Cystectomy in a Dog

A 6 yr old neutered male German shepherd dog was evaluated at a veterinary referral hospital following diagnosis of uroabdomen of unknown origin. A positive-contrast retrograde urethrogram identified diffusely irregular margins of the urinary bladder but no active leakage of urine into the peritoneal cavity. An abdominal ultrasound identified severe thickening and loss of wall layering of the apex of the bladder. The dog was initially managed with an indwelling urinary catheter; however, when the catheter was removed 5 days later, the dog developed a recurrent uroabdomen after an episode of dysuria. Subsequent surgical exploration identified numerous (>5), small (1-2 cm), black cyst-like nodules within the bladder wall at the apex of the bladder. A partial cystectomy, removing approximately 65% of the cranial bladder, was performed. Histopathology and immunohistochemistry of the bladder identified hemangiosarcoma of the bladder wall with chronic neutrophilic and hemorrhagic cystitis. The dog recovered from surgery without major complication and is still alive 9 mo following surgery. To the authors' knowledge, this is the first report of successful treatment of canine bladder hemangiosarcoma by partial cystectomy in a dog.

Giant pericardial-occupying compressive primary cardiac hemangiosarcoma in a cat

Hemangioarcoma in the cat is an infrequently diagnosed tumor, and cardiac involvement is rare. We report a previously healthy, 8-year-old, domestic shorthair cat with acute collapse associated with pericardial effusion and cardiac tamponade. Following pericardiocentesis and removal of 15 mL of fluid, the cat improved rapidly. A massive, space-occupying, intrapericardial tumor adhered to and compressing the right atrium and ventricle was detected by echocardiography. Approximately 5 weeks following initial presentation, bicavitary effusion and tachypnea developed, and the cat was euthanized. Necropsy revealed a giant intrapericardial mass adhered to and impinging upon the right heart. Histologic and immunohistochemical examination confirmed hemangiosarcoma with no gross or histologic evidence of metastasis. To the authors' knowledge, this is the first account of a pericardial-occupying, primary feline cardiac hemangiosarcoma resulting in compression of the right heart and cardiac tamponade, Further, this report describes novel clinicopathological relationships between radiographic and echocardiographic findings and gross and microscopic pathology.

A retrospective analysis of stereotactic body radiation therapy for canine heart base tumors: 26 cases

INTRODUCTION

This study retrospectively evaluated outcomes and adverse radiation effects (AREs) associated with stereotactic body radiation therapy (SBRT) for canine heart base tumors (HBTs). A secondary aim was to identify any demographic or echocardiographic factors that might determine which dogs would most benefit from SBRT.

ANIMALS

Twenty-six dogs that received SBRT for an imaging-based diagnosis of a HBT were evaluated.

METHODS

Twenty-three dogs were treated with three fractions of 10 Gy delivered daily or every other day. The remaining 3 dogs received variable protocols of one to five fractions. Demographic, echocardiographic, and radiographic information, AREs, and treatment responses were collected. Correlations of these data with survival time were evaluated.

RESULTS

The median overall survival time was 404 days (95% confidence interval: 239-554 days). The majority of dogs experienced a partial response (25%) or stable disease (60%) for a median duration of 333 days (95% confidence interval: 94-526 days). Three dogs had progressive disease within six months of SBRT. Radiographic pneumonitis was identified in 7 of 23 dogs, and clinical pneumonitis was identified in 4 dogs. No other AREs were noted. The rate of distant metastasis was 13%. On multivariate analysis, it was found that vena caval obstruction, supraventricular and ventricular arrhythmias, clinical signs, and enlarged locoregional lymph nodes at presentation were negatively associated with survival time.

CONCLUSIONS

Stereotactic body radiation therapy was delivered with a low rate and degree of normal tissue complications. Asymptomatic dogs with confirmed, progressive growth of a HBT may most likely benefit from SBRT.

Metastatic Cardiac Hemangiosarcoma in a 6 Year Old Wheaten Terrier Mix

A 6 year old Wheaten Terrier mix with a history of collapse and lethargy was referred for evaluation of pericardial effusion. The echocardiogram identified pericardial effusion and a right auricular mass. No sign of metastasis was noted at this time in thoracic radiographs and abdominal ultrasounds. The patient underwent the right auriculectomy via right lateral thoracotomy. Several metastatic masses were located in the visceral aspect of the pericardium at the time of surgery and were all excised. The right auricular mass and pericardial masses were diagnosed as hemangiosarcoma with a sign of metastasis. The patient recovered from surgery uneventfully and was discharged the sixth day after surgery. The patient received doxorubicin followed by cyclophosphamide, piroxicam and Coriolus versicolor extract postoperatively. Pulmonary metastases were noted 229 days and the dog was euthanized 318 days after surgery. No clinical signs were noted until 309 days postoperatively.

Histiocytic Sarcoma and Hemangiosarcoma Update

Histiocytic sarcoma (HS) and hemangiosarcoma (HSA) are uncommon and aggressive neoplasms that develop much more frequently in dogs than in cats. Breed-specific predispositions have been identified for both cancers. The development of novel diagnostics is underway and may aid in earlier diagnosis. Therapeutic approaches to HS and HSA depend on the stage of disease and may include surgery, radiation therapy, and chemotherapy. Such interventions improve outcome; however, aside from a small number of clinical circumstances, both diseases are considered largely incurable. Continued efforts toward the identification of driver mutations and subsequent druggable targets may lead to improvements in long-term prognosis.

Cardiac Leiomyosarcoma in a Cat Presenting for Bilateral Renal Neoplasia

A 10-year-old neutered female domestic longhair cat was presented to a tertiary care veterinary hospital for evaluation of a right renal mass that was identified incidentally on abdominal radiographs and classified further as a sarcoma based on fine needle aspiration cytology. Further diagnostic workup, including ultrasound and cytology, identified a sarcoma in the left kidney. After approximately 1 month of conservative medical management, the clinical condition deteriorated and the cat was humanely destroyed. Post-mortem examination confirmed bilateral renal masses with multifocal infarction and extensive necrosis, and further identified a large mass at the apex of the heart as well as multiple pulmonary nodules. Microscopical examination of the masses identified a population of poorly-differentiated neoplastic spindle cells, consistent with sarcoma. Immunohistochemically, the neoplastic cells expressed smooth muscle actin and muscle-specific actin, but were negative for myoglobin and factor VIII. Phosphotungstic acid-haematoxylin staining was unable to identify cross-striations in the neoplastic cells. Based on these results and the pattern of lesion distribution, the cat was diagnosed with cardiac leiomyosarcoma with pulmonary and bilateral renal metastasis.

Pericardial Hemangiosarcoma in a 10-Year-Old Papillon

A 10 yr old papillon was evaluated for lethargy, inappetence, tachypnea, and labored breathing. Physical examination findings included dehydration, tachypnea, tachycardia, and muffled heart sounds. Thoracic radiographs revealed an enlarged cardiac silhouette. Echocardiography revealed a mild volume of pericardial effusion and no evidence of right atrial tamponade or a cardiac-associated mass. Cytological analysis of the pericardial effusion was consistent with blood. There was no evidence of neoplasia. Coagulation parameters were within normal limits. Initial treatment consisted of pericardiocentesis. A subtotal pericardiectomy was later performed. No surgical complications were noted, and the dog was discharged 2 days following surgery. Results of the histological examination of the pericardium revealed hemangiosarcoma. Treatment with doxorubicin was initiated 12 days after surgery, at which time, pulmonary metastasis was suspected. The dog survived for 18 days after subtotal pericardiectomy, when it was euthanized because of complications presumably related to pulmonary metastatic disease. This is the first published report of primary pericardial hemangiosarcoma. The dog had a short survival time; thus, the response to subtotal pericardiectomy combined with adjuvant doxorubicin treatment could not be determined. Pulmonary metastatic disease was suspected 12 days following surgery. Based on this case report, pericardial hemangiosarcoma carries a guarded prognosis.

Use of metronomic chemotherapy in the management of a cat with abdominal haemangiosarcoma

CASE SUMMARY

A 12-year-old entire domestic shorthair was evaluated for a 5 week history of intermittent vomiting, loss of appetite and weight loss. Abdominal ultrasound revealed a multi-lobulated heterogeneous mass adjacent to the mesenteric vessels. Cytology from fine-needle aspirates was non-diagnostic. Histopathology from a Tru-cut biopsy was consistent with haemangiosarcoma. The cat was treated with metronomic chemotherapy using oral cyclophosphamide. The cat remained clinically well and was euthanased 10 months after diagnosis owing to development of a haemoabdomen.

RELEVANCE AND NOVEL INFORMATION

Prognosis of feline abdominal haemangiosarcoma is generally poor and limited information on treatment is available in the veterinary literature. The use of metronomic chemotherapy with oral cyclophosphamide in this cat provided a 10 month period of good-quality life.

Bilateral bronchial stent deployment for palliative treatment of a compressive intrathoracic mass in a cat

Case summary

Bronchial stents may be useful to relieve clinical signs of extraluminal compression. Herein we describe a case which, to our knowledge, is the first cat where bilateral bronchial stents have been used clinically. Respiratory signs of principal bronchial compression were alleviated after the stent procedure. Minor complications occurred, specifically: severe hypoxia during stent deployment; a transient, self-limiting postoperative pneumothorax possibly associated with ventilation-induced lung injury; bronchopneumonia (possibly pre-existing); and transient worsening of cough postoperatively. Stents were well- tolerated long- term. The cat was euthanased at 44 weeks post-stent procedure, owing to clinical signs of regurgitation, seemingly related to oesophageal dysfunction associated with tumour invasion.

Relevance and novel information

In this case, it appeared that bronchial stents were feasible and the procedure was associated with long-term improvement in respiratory signs related to extraluminal bronchial compression.

Left ventricular cardiac myxoma and sudden death in a dog

Background

Myxoma is a very rare benign cardiac tumor in dogs. This is the first description of a cardiac myxoma originating from the left ventricular outflow tract, presumably causing sudden death.

Case presentation

A previously healthy 12-year-old male West Highland white terrier was found dead during its 1-week stay in a kennel. The dog was known to have a cardiac murmur. On necropsy, a pedunculated neoplasia was found attached to the interventricular aspect of the left ventricular outflow tract, resulting in almost complete obstruction of the aorta. As this was the only abnormality identified, the tumor was considered as the cause of sudden death. Histopathologic findings were compatible with a myxoma.

Conclusions

Benign intraluminal tumors of the heart are very rare in dogs, but may have fatal consequences. Echocardiography could have revealed the cause of the cardiac murmur of this previously asymptomatic dog. Surgical removal could have been possible, as the tumor was pedunculated.

Cytological diagnosis of cardiac masses with ultrasound guided fine needle aspirates

BACKGROUND

Cardiac masses are uncommon in the canine population. When present, an attempt should be made to obtain a definitive diagnosis. Our goal with this case series was to report that as long as anatomic location permits, obtaining fine needle aspirates (FNAs) for cytological evaluation is practical, safe, and may provide a definitive diagnosis.

METHODS

Our database has been retrospectively searched for cases where FNA of cardiac masses have been performed.

RESULTS

A total of six cases were retrieved. Four dogs were under general anaesthesia and two were sedated. Ultrasound guided transthoracic FNAs were obtained in all cases with only minor complications: mild self-limiting pericardial effusion (n = 1) and one ventricular ectopic complex (n = 1). All dogs were closely monitored during the procedure (pulse oximetry, electrocardiography and blood pressure). A diagnosis was obtained in all cases: inflammation (n = 1), haemangiosarcoma (n = 2), sarcoma (n = 2) and chemodectoma (n = 1).

CONCLUSION

A cytological diagnosis allows clinicians to make appropriate clinical decisions, has dramatic impact on treatment recommendations and gives information about prognosis.

A descriptive review of cardiac tumours in dogs and cats

Cardiac tumours are uncommon in the canine and feline population and often an incidental finding. Common types include haemangiosarcoma (HSA), aortic body tumours (chemodectoma and paraganglioma) and lymphoma. These neoplasms can cause mild to severe, life-threatening clinical signs that are independent of the histological type and may be related to altered cardiovascular function or local haemorrhage/effusion into the pericardial space. Cardiac tumours may require symptomatic treatment aimed at controlling tumour bleeding and potential arrhythmias, and other signs caused by the mass effect. Additional treatment options include surgery, chemotherapy and radiotherapy. For all medical therapies, complete remission is unlikely and medical management, beyond adjunctive chemotherapy in HSA, requires further investigation but combination chemotherapy is recommended for lymphoma. The aim of this report is to summarize and critically appraise the current literature in a descriptive review. However, interpretation is limited by the lack of definitive diagnosis and retrospective nature of most studies.

Histology and Clinical Outcome of Benign and Malignant Vascular Lesions Primary to Feline Cervical Lymph Nodes

A novel form of primary feline hemangiosarcoma and additional cases of plexiform vascularization in the cervical lymph nodes are reported. Sixteen cases of feline lymphadenopathy attributed to abnormal vascular proliferation were identified and evaluated. Most of these lesions were diagnosed histologically as hemangiosarcoma. However, lesions of plexiform vascularization, with and without areas of putative malignant transformation, were also identified. Mean age of the cats was 11 years (range, 3–16 years) with most being domestic shorthair and medium hair (13). Two domestic long hair and 1 Maine Coon were identified. Excisional nodal biopsy was performed in 15 cases and incisional biopsy in 1 case. Six cats were euthanized due to their disease. Survival times ranged from ≤1 month to ≥30 months. We provide a new clinical differential for cervical lymphadenopathy in cats that is not widely recognized. Proper identification of primary nodal vascular lesions in cats will enable further characterization of clinical features and biologic behavior to determine specific therapy.

Imaging diagnosis--ultrasonographic appearance of small bowel metastasis from canine mammary carcinoma

A 10-year-old entire female Beagle dog was evaluated for an acute history of lethargy, anorexia, and diarrhea. Mammary tumors were detected during physical examination. Ultrasonographic scanning revealed the presence of a unique pattern of multiple, well-defined and well-marginated hypoechoic nodules in the muscularis layer of the jejunum. These nodules were not associated with changes in the rest of the normal intestinal layering and were not causing signs of intestinal obstruction. Mammary carcinoma metastases to the intestinal muscularis layer were diagnosed based on histopathological examination.

Whole body computed tomographic characteristics of skeletal and cardiac muscular metastatic neoplasia in dogs and cats

Muscular metastatic neoplasia has been reported to be rare in domestic animals, however previous studies were based primarily on necropsy findings. The purpose of this retrospective study was to describe whole body computed tomography (CT) characteristics of confirmed muscular metastases in a cohort of dogs and cats presented for oncology evaluation. Medical records of 1201 oncology patients were reviewed. Included animals underwent pre and postcontrast whole body CT, and CT-guided tru-cut biopsy or fine needle aspiration of one or more metastatic lesions. Twenty-one dogs and six cats met inclusion criteria, representing 2.08% of all canine oncology patients and 3.1% of all feline oncology patients. Mean age was 9.6 years. Postcontrast CT characteristics included well-demarcated, oval-to-round lesions with varying enhancement patterns: ring enhancing (n = 16), heterogeneously enhancing (n = 8), or homogeneously enhancing (n = 5). Five animals showed concurrent and varying nodular patterns. In seven cases (five dogs and two cats), one single muscular nodule was observed. In 20 cases, two or more lesions were observed. In two cases, cardiac hypodense nodules were observed in the postcontrast CT, while appearing isodense in the precontrast study. Necropsy confirmed neoplasia in both of them. Locations of muscular metastases included epaxial/paraspinal muscles of the cervical, thoracic, and lumbar spine (n = 18), superficial muscles of the thoracic wall (n = 13), scapular/shoulder region (n = 3), hind limb (n = 3), and abdominal wall muscles (n = 1). Findings supported the use of pre and postcontrast whole body CT for oncologic staging in dogs and cats, especially for primary tumors characterized by a high metastatic rate.

A Comparative Review of Canine and Human Rhabdomyosarcoma With Emphasis on Classification and Pathogenesis

Rhabdomyosarcomas are a diverse group of malignant mesenchymal neoplasms exhibiting variable levels of differentiation toward skeletal myocytes. Neoplastic cells may resemble relatively undifferentiated myoblasts, satellite cells, or more differentiated elongated spindle cells and multicellular myotubes. In veterinary medicine, classification into subtypes and variants is based on an outdated system derived from human pathology and is solely based on histologic characteristics. In contrast, classification of human rhabdomyosarcoma is based on histologic, immunohistochemical, and molecular diagnostic techniques, and subclassification has clinical and prognostic relevance. Relevance of tumor subtyping has not been established in veterinary medicine. Recent discoveries of components of the molecular pathogenesis and genomes of human rhabdomyosarcomas have led to new diagnostic techniques and revisions of the human classification system. The current classification system in veterinary medicine is reviewed in light of these changes. Diagnosis of rhabdomyosarcoma using histopathology, electron microscopy, and the clinical aspects of human and canine rhabdomyosarcomas is compared. The clinical features and biologic behavior of canine rhabdomyosarcomas are compared with canine soft tissue sarcomas.

Prevalência e aspectos anatomopatológicos das neoplasias primárias do coração, de tecidos da base do coração e metastáticas, em cães do Sul de Minas Gerais (1994-2009)

Este estudo teve como objetivo determinar a prevalência e achados anatomopatológicos de tumores primários e metastáticos do coração ou de tecidos da base do coração, diagnosticados em caninos do Sul de Minas Gerais. O diagnóstico foi realizado mediante análise histopatológica e imuno-histoquímica das neoplasias. Durante os anos de 1994-2009, foram realizadas 2397 necropsias em caninos. Neoplasias no coração foram detectadas em 31 cães (1,29%), onde, sete (22,58%) eram primárias e 24 (77,42%) metastáticas. As neoplasias diagnosticadas como primárias do coração foram o hemangiossarcoma (1/7) e o mixoma (1/7); e como primárias da base do coração o quimiodectoma (3/7) e o carcinoma de tireoide ectópica (2/7). A frequência foi maior em cães machos (5/7), da raça Boxer (3/7) e com idade média de 9,7±1,88 anos. Nas neoplasias metastáticas, a frequência foi maior em fêmeas (15/24), em cães da raça Rottweiler (7/24) e a idade média foi de 7,5±3,23 anos, sendo o linfoma de células T a neoplasia metastática de maior ocorrência (7/27).