Aneurysmal dilatation of the right auricle in two dogs

An 8-year-old sexually intact male Golden Retriever with a history of collapse during exercise underwent an examination during which tachydysrhythmia was identified. At another institution, a 12.5-year-old spayed female Lhasa Apso was referred because of a cough and for evaluation of a heart murmur. In the Golden Retriever, radiographic examination revealed bulging of the craniodorsal aspect of the cardiac silhouette and echocardiography revealed right atrial dilatation. In the Lhasa Apso, a cranial mediastinal mass was suspected on the basis of radiographic findings, but no abnormalities were detected echocardiographically. In both dogs, nonselective angiography and contrast-enhanced computed tomography revealed a markedly enlarged, thin-walled right auricle. Exploratory thoracotomy in the Golden Retriever revealed a defect in the pericardium through which the right auricle and part of the atrium had herniated. In dogs, a right auricular aneurysm should be considered in differential diagnoses of a cranial mediastinal mass (detected radiographically) adjacent to the cardiac silhouette.     

Echocardiographic,thoracic ultrasonographic,and CTA diagnosis of pericardial neoplasia in a dog

A 12-year-old male neutered Yorkshire Terrier presented for coughing and respiratory distress. Transthoracic echocardiography initially misdiagnosed the patient with pericardial effusion; repeat echocardiography increased suspicion for neoplasia. A definitive diagnosis was not apparent. Findings on thoracic computed tomography and thoracic ultrasound were consistent with a diffusely thickened, heterogenous, hypoechoic soft tissue structure surrounding the heart. Fine needle aspirates were obtained using ultrasound guidance and routine cytology of the intrapericardial mass was consistent with neoplasia, with pericardial mesothelioma most likely. These novel findings highlight the importance of thoracic ultrasound and potential limitations of echocardiography in diagnosis of pericardial neoplasia.     

Septic pericarditis, aortic endarteritis, and osteomyelitis in a dog

A 7-year-old, female spayed rottweiler was referred with a history of an acute onset of collapse attributable to cardiac tamponade. Thoracic radiographs revealed an enlarged cardiac silhouette compatible with pericardial effusion, sternal osteomyelitis, and an unusual mineralized lesion determined later to be within the aortic wall. The pericardial effusion was a septic exudate secondary to infection with Staphylococcus species and hemorrhage into the pericardium through a mineralized aortic lesion. The case demonstrates the importance of complete evaluation of thoracic radiographs in a patient with cardiac disease and the potential value of cytopathological evaluation of pericardial fluid.     

Malignant B-cell lymphoma of the Harder's gland in a rabbit

A 22-month-old, female rabbit was presented with a 1-day history of acute unilateral exophthalmos. Ultrasonography and computed tomography (CT) of the orbit revealed an orbital mass. Retrobulbar lymphoma was diagnosed following fine-needle aspiration biopsy (FNAB). Thoracic radiographs were normal, and ultrasonography of the abdomen showed focal hypoechoic thickening of the bowel wall and hypoechoic enlarged lymph nodes. The rabbit was euthanized and histopathology identified the retrobulbar mass as B-cell malignant lymphoma of the Harder's gland. Mesenteric lymph nodes, caecum, and both kidneys were also affected. This is the first documented case of malignant lymphoma of the Harder's gland in a rabbit.     

Aortic body chemodectoma causing pulmonary oedema in a cat

A seven-year-old male domestic shorthaired cat was presented with persistent dyspnoea. Thoracic radiography and echocardiography revealed pulmonary oedema and a mass at the base of the heart. At necropsy the mass was found to be an aortic body chemodectoma that had metastasised to the sternal lymph node. This is a rare tumour in the cat, the third reported case where there was evidence of metastasis, and only the second reported case where there was evidence of lymphocytic infiltration of the primary tumour. Pulmonary oedema is an unusual presentation of this tumour in the cat.     

Complex mammary carcinoma with metastases to lymph nodes,subcutaneous tissue,and multiple joints in a dog

An 8‐year‐old, intact female, mixed‐breed dog presented to the Oklahoma State University Boren Veterinary Medical Teaching Hospital for evaluation of progressive lameness and joint effusion of multiple joints. Physical examination revealed joint effusion of the elbow, hock, and stifle joints bilaterally, enlarged left axillary and right popliteal lymph nodes, a subcutaneous mass over the left elbow, and a subcutaneous mass involving the left second and third mammary glands. Cytologic examination of the mammary mass, enlarged lymph nodes, and joint fluid from most affected joints revealed a monomorphic population of loosely cohesive neoplastic epithelial cells. The patient was humanely euthanized, and subsequent necropsy with histopathologic examination revealed a complex mammary carcinoma with metastases to enlarged lymph nodes, subcutaneous tissue over the left elbow, and the synovium of multiple joints. Immunohistochemical stains were performed and showed diffusely positive pan cytokeratin, CK8/18, and CK19 staining in the neoplastic luminal epithelial cells of the mammary carcinoma, synovium, and lymph nodes, and showed diffusely positive vimentin staining of the myoepithelial cells. Myoepithelial calponin positivity was diffuse in the mammary mass and lymph nodes but minimal in the synovium. Only the mammary mass showed p63 positivity. Metastatic mammary neoplasia is relatively common in dogs; however, metastasis to the synovium has only been reported once previously in the literature. This is the first case utilizing immunohistochemistry for confirmation and characterization of metastases.     

Constrictive pericarditis in a mare: attempted treatment by partial pericardiectomy.

Chronic constrictive pericarditis was diagnosed in a 6-year-old Thoroughbred mare based on the clinical findings of right congestive heart failure, hyperechoic pericardium without pericardial effusion, and a dip-and-plateau shape of the right ventricular pressure curve with equilibration of the diastolic pressures in all cardiac chambers. Treatment was attempted by partial pericardiectomy using a right lateral thoracotomy approach. Because of severe epicardial involvement recurrence of the constrictive pathology was noted 6 weeks after the surgical procedure. However, in selected cases in which the disease process is limited to the pericardium, partial pericardiectomy may offer a mode of therapy in horses suffering from constrictive pericarditis.     

DILATED CORONARY SINUS IN A DOG WITH PERSISTENT LEFT CRANIAL VENA CAVA

This paper describes the electrocardiographic, echocardiographic (two-dimensional, M-mode, contrast and Doppler) and non-selective angiocardiographic features in a 3 year old female Beagle with dilated coronary sinus due to persistent left cranial vena cava. Negative P waves in leads III and aVR and a positive P wave in lead aVL were seen. Echocardiographically, a hipoechoic circular structure was seen between the left atrium and the pericardium in the area where the coronary sinus is located. A velocity pattern with two peaks was obtained, one systolic with velocity = 0.44 ± 0.05 m/sec and the other diastolic with velocity = 0.27 ± 0.01 m/sec. By M-mode echocardiography, at level of the aorta and the left atrium, a linear structure was identified between the left atrium and the pericardium; this structure was characterized by phasic movements of the anterior wall during the cardiac cycle. Following a left cephalic vein injection of saline, bubbles were seen within the coronary sinus; when saline was injected into the right cephalic vein, bubbles were also seen within the coronary sinus and right atrium and ventricle. Non-selective angiocardiography confirmed a dilated coronary sinus with persistent left cranial vena cava. The right cranial vena cava was absent. The dog was clinically normal and the unusual vessel was an incidental finding.     

Intrapericardial cyst causing cardiac tamponade in a cat

A two-year-old cat with episodic dyspnea was diagnosed with an intrapericardial cyst via two-dimensional echocardiography. The cyst directly compressed the right ventricle, resulting in cardiac tamponade. Centesis of the cyst was performed to reduce tamponade prior to surgery. At surgery, a large, fluid-filled cystic structure was found within the pericardium. The cystic structure was continuous with a pedicle of liver that passed through a small peritoneopericardial diaphragmatic hernia. Surgical resolution was achieved by median sternotomy, midline pericardotomy, resection of the cyst, and diaphragmatic herniorrhaphy.     

Metastatic osteosarcoma tumor thrombus in a Cavalier King Charles Spaniel presenting with dyspnea

A six-year-seven-month-old female neutered Cavalier King Charles Spaniel was referred for the investigation of progressive dyspnea and hyphema in the right eye with secondary glaucoma. Previous medical history included a high-grade soft tissue spindle cell sarcoma removed from the cranial sternal region one year before.On presentation at the referral hospital, the dog was tachypneic and dyspneic. The heart rhythm was regular and there was a soft left-sided systolic murmur. Echocardiography identified the presence of a mass significantly occluding left heart inflow, with no other lesions identified. Thoracic radiographs documented a localized alveolar pattern within the left caudal lung lobe. The size of the heart and pulmonary vessels were within normal limits, indicating a non-cardiogenic alveolar pattern.Given the clinical presentation of dyspnea and high index of suspicion of intra-cardiac neoplasia, the dog was considered to have a grave prognosis and therefore euthanized. Post-mortem gross and histopathologic examination revealed the presence of a metastatic osteosarcoma tumor thrombus in the left atrium and pulmonary vein, metastatic osteosarcoma infiltrating the myocardium, lungs, the uveal tract of the right eye, and both adrenal glands. Whitney grade II myxomatous changes were noted on the mitral and tricuspid valve leaflets.This report describes an unusual intra-cardiac tumor thrombus in a dog presenting with dyspnea. Cavalier King Charles Spaniels presenting with dyspnea often raise suspicion for myxomatous mitral valve disease. However, as demonstrated in this case, other more unusual causes of dyspnea should also be considered in the absence of classic clinical findings.     

Embolised mesothelial cells in a tracheobronchial lymph node associated with idiopathic chylopericardium in a dog

A 5·5‐year‐old male castrated Bernese mountain dog presented with respiratory difficulties and was diagnosed with haemorrhagic pericardial effusion which transformed into chylopericardium. Thoracic duct ligation and subtotal pericardiectomy in combination with biopsy of an enlarged tracheobronchial lymph node were performed. Multiple clusters of mesothelial cell emboli were observed in the subcapsular sinus of the lymph node. No causative agent for the pericardial effusion could be identified, suggesting that this is a case of mesothelial cell embolisation associated with idiopathic ‐chylopericardium in a dog.     

Cor triatriatum dexter of unusual morphology in a miniature schnauzer

A five-year-nine-month-old, male entire, miniature schnauzer presented for further investigation of pleural effusion. Echocardiography revealed a perforated membrane dividing the right atrium into two chambers: the true right atrium (a small, lower-pressure, cranioventral chamber communicating with the tricuspid valve and right ventricle) and the accessory right atrium (a larger, higher-pressure, caudodorsal chamber), consistent with a cor triatriatum dexter. This was confirmed using computed tomography angiography. Imaging studies revealed that both the cranial and caudal vena cava entered the higher-pressure accessory right atrium and the coronary sinus entered both the accessory and true right atrial chambers. This differed from the more usual canine cor triatriatum dexter presentation with the cranial vena cava entering the lower-pressure cranial chamber and the caudal vena cava entering the higher-pressure caudal chamber. Balloon membranostomy was successful in reducing the pressure gradient between the two right atrial chambers with subsequent resolution of the clinical signs. The patient continues to do well after three-years of follow-up.     

Echocardiographic Features of Giant Right Atrial Diverticulum in a Dog

A 12‐year‐old spayed female miniature Poodle presented for coughing, respiratory distress, and anorexia. After thoracentesis for pleural effusion, radiography revealed an enlarged cardiac silhouette with a bulge in the area of the body of the right atrium. Echocardiography revealed an anechoic chamber‐like cavity lateral to the right atrium that communicated with the right atrium through a 13 mm defect in the right atrial free wall. Contrast echocardiography and color flow Doppler were used to prove that the cavity communicated with the right atrium. The cavity was diagnosed as a giant right atrial diverticulum.     

Mineralized,obstructive cardiac myxoma with chondroid differentiation in a cocker spaniel

A 12-year-old castrated male cocker spaniel dog was referred for evaluation of signs consistent with right-sided heart failure. Thoracic radiography revealed mineralization in the region of the right atrium. Echocardiography identified a mass partially filling the right atrium and right ventricle and obstructing flow through the right heart. These findings were confirmed at necropsy and histopathologic features were consistent with myxoma with chondroid differentiation.     

Pleural effusion secondary to metastasis of an ovarian adenocarcinoma in a horse

An 11-year-old Quarter Horse mare was presented with ventral edema and pleural effusion, secondary to a disseminated ovarian adenocarcinoma. Bilateral thoracocentesis yielded 30 L of thin, blood-tinged fluid, which was a modified transudate. Cytologic examination of the fluid revealed large atypical cells, suggestive of carcinomatous neoplasia. Similar cells were found in the peritoneal fluid. The mare was euthanatized. Necropsy revealed a 35-cm diameter mass in the cranial mediastinum, ventral to the trachea. The left ovary was 25 cm in diameter and most of the parenchyma was replaced by red or brown friable tissue, containing numerous 1-to 3-mm cysts. Papillary adenocarcinoma of the ovary was diagnosed, based on the appearance and arrangement of tumor cells in the ovary, sublumbar and tracheobronchial lymph nodes, and mediastinal mass. Ovarian neoplasia should be considered in the differential diagnosis of pleural effusion in the horse.     

Partial anomalous pulmonary venous connection in a dog

A 2-year-old male intact Belgian Malinois was presented for exercise intolerance. A grade III/VI left basilar systolic murmur was detected. Echocardiography revealed moderate right atrial and ventricular dilation and increased pulmonic outflow velocity. Thoracic radiographs showed right heart enlargement and a dilated caudal vena cava. In addition, on the left lateral projection, an enlarged aberrant right cranial pulmonary lobar vein was suspected to be diverging ventrally from the course of the right cranial lobar bronchus and inserting more ventrally than normal in the region of the right atrium. A left-to-right pulmonary vascular shunt was suspected, and the patient underwent further diagnostics under general anesthesia. An agitated saline study was positive, suggestive of a concurrent right to left shunt. A right heart catheterization was performed. Angiography was inconclusive. Oximetry testing revealed an increase in oxygen saturation within the right atrium at the level of the caudal cava supportive of a left-to-right shunt in this region. Computed tomography angiography revealed a large single pulmonary vein that anomalously entered into the caudolateral aspect of the right atrium (left-to-right shunt) and was suspicious for a small arteriovenous malformation between the right caudal pulmonary artery and the right pulmonary vein returning to the left atrium (right to left shunt). The patient was diagnosed with a partial anomalous pulmonary venous connection and a possible arteriovenous malformation.     

Radiographic characterization of enlarged sternal lymph nodes in 71 dogs and 13 cats

In this retrospective study, radiographically enlarged sternal lymph nodes (LNs) were evaluated in 71 dogs and 13 cats for average size, location, and most representative radiographic view. Concurrent clinical diagnoses were also noted and grouped into one of three following categories: neoplastic, inflammatory, or hematologic. There were no statistically significant differences in LN size between lateral views within each species. Enlarged sternal LNs were more cranially positioned in dogs than cats. No statistical difference was noted between right and left laterals, as to on which projection the enlarged sterna lymph nodes was seen best. Neoplastic disease (78.9%) was the most prevalent condition seen in association with LN enlargement in dogs, followed by primary infectious or inflammatory diseases (14.1%) and various hematologic conditions (7.0%). In cats, neoplasia was also most common (69.2%), followed by inflammatory diseases (30.8%). No hematologic conditions were noted in cats. The most common etiologic agent seen concurrently with enlarged sternal LNs in both dogs (33.8%) and cats (38.5%) was malignant lymphoma. The results of this study provide a clinically useful representation of the average size and location of radiographically enlarged sternal LNs for dogs and cats. The diseases represented demonstrate the wide spectrum of potential causes of sternal lymphadenopathy.     

USE OF COMPUTED TOMOGRAPHY TO EVALUATE THE INTESTINAL TRACT OF ADULT LLAMAS

In the llama, signs of colic are obscure and may be exhibited as persistent sternal recumbency and anorexia even in the presence of a surgical lesion. Diagnostic methods for evaluation of abdominal disorders are limited. As a result, surgical intervention may be prolonged and increase the risk of mortality and postoperative complications. The objective of this study was to determine the feasibility of computed tomography to evaluate the llama intestinal tract. Eighteen hours prior to the computed tomography scan, six llamas were given barium sulfate (15%) via an orogastric tube. Following induction of general anesthesia, the llamas were positioned in sternal recumbency, and 10 mm contiguous slices were obtained from the diaphragm to the tuber ischiadicum. Structures that were consistently identified included the first, second, and third compartments (C1, 2, and 3), small intestine, spiral colon, and ascending colon. C1 was easily identified in the cranial aspect of the abdomen due to its large size relative to the other compartments and characteristic saccules. C2 was located cranial, ventral, and to the right of Cl, while C3 was visualized as a tubular structure to the right and ventral to C1 and C2, C3 was traced caudally until it turned dorsally and continued cranially to a dilated ampulla in the right cranial abdomen delineating the entrance to the small intestine. The spiral colon was identified consistently in the left ventral caudal abdomen. Structures that could not be conclusively identified included the cecum and mesenteric lymph nodes. Computed tomography allowed a consistent evaluation of the major intestinal structures associated with colic in the llama. Thus, computed tomography is a potentially valuable noninvasive diagnostic tool to effectively evaluate the abdominal cavity and differentiate medical from surgical lesions in the llama.     

Clinical diagnosis of aneurysm of the right coronary artery in a white cockatoo (Cacatua alba)

A 16-year-old male white cockatoo was presented with lethargy and a decreased appetite. Auscultation between the second and third sternal rib revealed a heart murmur, which was confirmed by electrocardiographic and phonocardiographic examination to be systolic, with a shift of the heart axis to -152°. Radiographs showed lack of detail in the cranial part of the abdominal coelom, indicative of ascites and an enlarged cardiac shadow, while ultrasonographic examination revealed pericardial effusion and fluid accumulation in the cavitas peritonealis hepatica. An extra fluid-filled cavity was found at the atrioventricular junction in the right cardiac wall and colour Doppler examination demonstrated a turbulent jetstream of blood into the cavity, originating directly above the aortic valve. Non-selective angiocardiography confirmed the ultrasonographic observations. Findings were indicative of an aneurysm of the a. coronaria dextra (right coronary artery). This was confirmed by necropsy which revealed atherosclerosis to be the underlying cause.     

COMPUTED TOMOGRAPHY CHARACTERISTICS OF CANINE TRACHEOBRONCHIAL LYMPH NODE METASTASIS

Tracheobronchial lymph node evaluation is critical for accurate staging of canine thoracic neoplasia and is more accurately achieved with computed tomography (CT) than radiography. Thoracic CT scans of 18 canine patients with known tracheobronchial lymph node histopathology and 10 clinically normal dogs were compared to establish if enlargement or contrast enhancement pattern correlated with metastatic status. Absolute lymph node size and three anatomically normalized lymph node ratios were significantly correlated with metastasis or severe granulomatous lymphadenitis (P<0.0003). Transverse maximum lymph node diameter of 12 mm or lymph node to thoracic body ratio of 1.05 are proposed cutoffs, above which metastatic involvement is very likely; however, only minimal accuracy was gained with normalized ratios. Lymph node contrast enhancement pattern was also significantly correlated to disease. A heterogenous and/or ring pattern was related to metastatic disease (P=0.03). Recommended protocol for CT examination of the tracheobronchial lymph nodes is 1–1.5 mm slices and intervals, intravenous contrast, and control of respiratory motion.