Angiosarcoma in cats

In a survey of 3145 feline necropsies at The Animal Medical Centre, eighteen cases of haemangiosarcoma and one case of lymphangiosarcoma were diagnosed. The haemangiosarcomas were primarily located in the spleen (four), liver (six), mesentery (four), mediastinum (three) and the lungs (one). The lymphangiosarcoma was seen in the skin and subcutaneous tissue of the abdominal wall and thighs. The clinical, macroscopic, and microscopic features of these tumours have been described. The most common clinical signs in the case of haemangiosarcoma were due to the rupture of the primary or metastatic neoplasms (70%). Metastases wese observed in 67% of the cases. Three main histological types (1, cavernous; 2, solid; and 3, capillaries separated by stroma) were observed, although mixtures of more than one histological type were seen in any one particular tumour. Rare cases of pulmonary haemangiosarcoma and lymphangiosarcoma in the cat have also been described.     

Role of computed tomography angiography in the differentiation of feline truncus arteriosus communis from pulmonary atresia with ventricular septal defect

Two domestic shorthair cats, a 6-month-old castrated male and a 7-month-old intact female, were diagnosed with complex congenital heart disease. Transthoracic echocardiography in both cats revealed a dilated arterial trunk overriding the interventricular septum with a large ventricular septal defect. The pulmonary trunk and branch pulmonary arteries were not visible using standard echocardiographic views in either cat. The differential diagnosis for both cats included truncus arteriosus communis vs. pulmonary atresia with ventricular septal defect. Each cat underwent computed tomography angiography to determine the origin and extent of the pulmonary blood supply and to better define extra-cardiac anatomy. Computed tomography angiography led to a diagnosis of truncus arteriosus communis with unrestricted pulmonary blood flow in one cat, whereas the other cat was diagnosed with pulmonary atresia with ventricular septal defect and major aortopulmonary collaterals serving as the primary source of pulmonary blood flow. Computed tomography angiography allowed for the ante mortem differentiation of truncus arteriosus communis from pulmonary atresia with ventricular septal defect in these two cats, leading to an accurate diagnosis and providing valuable information to therapeutic decision-making for each case.     

Cutaneous lymphangiosarcoma in a young dog: clinical, anatomopathological and lectinhistochemical description

Lymphangiosarcoma is a rare tumour in domestic animals arising from lymphatic endothelial cells. Occasionally, microscopic differentiation with haemangiosarcoma may be difficult. The aim of the present study was to describe a lymphangiosarcoma in a 1-year-old female Doberman Pinscher dog and to characterize its lectinhistochemical binding pattern as compared with that of haemangiosarcoma. The dog was presented because of a cutaneous painful swelling located in the left axilla. Histological diagnosis confirmed lymphangiosarcoma. The dog was killed. Necropsy revealed mediastinal lymph nodes' involvement. Twenty lectins were tested in tissue sections of this case as well as in four haemangiosarcomas from other dogs. Staining intensity was issued upon optical density determinations. Percentage of lectinhistochemical staining area was also conducted. RCA-I showed the most intense and wide distributed labelling pattern for lymphangiosarcoma. PHA-E was the counterpart for haemangiosarcoma. Should similar results be obtained in further studies, such differences could aid in the differential diagnosis between lymphangiosarcoma and haemangiosarcoma when histological pictures were not conclusive.     

Chylothorax in a dog with pulmonary lymphangiosarcoma

Lymphangiosarcoma of the pulmonary pleura was found to be the cause of persistent chylothorax in an eight-year-old, intact male golden retriever. After a two-month course of medical management, a lymphangiogram and thoracic duct ligation were performed with the objective of decreasing further effusion. At surgery, gross lung pathology was biopsied and yielded a histopathological diagnosis of pulmonary pleural lymphangiosarcoma. A relatively rare tumor, lymphangiosarcoma of the pulmonary pleura has not previously been documented as a source of chylothorax in the dog.     

Pneumonectomy: four case studies and a comparative review

Pneumonectomy is the resection of all lung lobes in either the left or right lung field. The surgical technique and postoperative results of pneumonectomy for clinical disease have not been reported in companion animals. Pneumonectomy was performed in three dogs and one cat to treat pulmonary or pleural disease, and the postoperative outcome compared with the complications and results reported in the human literature. One dog died immediately postoperatively due to suspected respiratory insufficiency and the remaining three animals survived the perioperative period. Postoperative complications were reported in two animals. Cardiac complications occurred in the cat, with perioperative arrhythmias and progressive congestive heart failure. Gastrointestinal complications were diagnosed in one dog, with mediastinal shift and oesophageal dysfunction. Left- and right-sided pneumonectomy is feasible in companion animals, and the postoperative outcome and complications encountered in this series were similar to those reported in humans.     

Multimodality imaging characteristics of tension pyopneumothorax secondary to pulmonary carcinoma in a cat

A 3‐year‐old Himalayan cat was presented with respiratory distress. Radiography showed multiple gas opacity foci, with the locations dependent on patient positioning, and severe pleural effusion with a contralateral mediastinal shift. A large volume of fluid and air was aspirated, and the fluid components were consistent with a nonseptic exudate. A pulmonary mass, pleural nodules, and an air–fluid interface with air bubbles trapped in fibrous septations were identified using thoracic ultrasonography and CT. The cat died 2 days after imaging studies. Necropsy revealed tension pyopneumothorax caused by pulmonary carcinoma and multiple pleural metastases.     

Feline lymphangiosarcoma--definitive identification using a lymphatic vascular marker

Abstract   Three cases of feline exudative dermatitis associated with lymphangiosarcoma are described. The animals, an 11-year-old, neutered male and two 10-year-old, neutered female short hair European cats, presented with a 2-month history of transparent liquid oozing from the skin of the groin and caudal abdomen. On physical examination the neutered male cat and one of the females were slightly depressed and showed loss of weight. Skin lesions were similar in all cats and characterized by the presence of alopecia and moist dermatitis in the ventral abdomen, groin and inner thigh. The hair at the periphery appeared matted by the fluid. In all three cases, histopathological examination of skin biopsies from the abdomen identified poorly defined neoplasia involving dermis and subcutis, characterized by proliferation of spindle cells aligned along pre-existing collagen bundles. The dissection of collagen bundles gave rise to irregular shaped anastomosing, often blind-ending vascular channels and trabeculae. Vascular spaces were mostly optically empty. These histological features were strongly suggestive of lymphangiosarcoma. Neoplastic cells were positive for the blood vascular marker Von Willebrand factor, and a lymphatic vascular marker LYVE-1 (Lymphatic Vessel Endothelial receptor – 1), demonstrating the mixed vascular origin of the tumour. Ultrastructural findings confirmed the final diagnosis of lymphangiosarcoma.     

Malignant histiocytosis in a domestic cat: cytomorphologic and immunohistochemical features

Malignant histiocytosis (MH) was diagnosed in a 13-year-old neutered male Domestic Shorthair cat on the basis of light microscopic and immunohistochemical findings. Thoracic fluid analysis showed a modified transudate which contained a very few atypical discrete cells. Cytologic and histologic evaluation of mediastinal and splenic masses revealed a pleomorphic population of large, discrete, round cells 10 to 30 micrometers in diameter with marked cellular atypia. Nuclei were oval to reniform, often with prominent, bizarre nucleoli. Multinucleated cells and mitotic figures were commonly seen. Erythro- and leucocytophagia were noted. Immunohistochemistry indicated a scattered positive staining pattern with the histiocytic antigenic marker Mac387 and a minor population of cells showing positive reactivity for lysozyme. This report describes the characterization of MH in a cat and emphasizes that MH should be considered as a differential diagnosis in proliferative disorders of discrete-cells in this species.     

Ante-mortem diagnosis of persistent truncus arteriosus in an 8-year-old asymptomatic dog

Persistent truncus arteriosus (PTA) was diagnosed in an 8-year-old neutered male Poodle referred for echocardiographic examination prior to anesthesia for surgical correction of bilateral cataract. A single large artery limited by a bicuspid valve and overriding both ventricles was observed with 2 distinct pulmonary arteries arising from the common arterial trunk. A large size interventricular septal defect was associated with a low velocity bidirectional shunt. The lesion was identified as a Type 3 PTA according to Collett and Edwards' classification. Although no clinical signs were reported, the dog presented polycythemia (packed cell volume = 68%) at the time of diagnosis. To our knowledge, this is the first report of an echocardiographic diagnosis of PTA in the dog. Until now, the ante-mortem diagnosis of this congenital heart disease has only been described in the cat. This case is also of interest because of the age of the animal and the total absence of cardio-respiratory signs at the time of diagnosis.     

Pulmonary lymphomatoid granulomatosis in a cat.

Pulmonary lymphomatoid granulomatosis was diagnosed in a 9-year-old castrated male domestic shorthair cat with a history of coughing, lethargy, and anorexia. Radiographic examination revealed multiple pulmonary opacities, consolidation of left lung lobes, and enlarged tracheobronchial lymph nodes. Cytologic examination of impression smears of abnormal pulmonary tissue revealed erythrocytes, lymphocytes, and macrophages, with scattered atypical lymphocytes and binucleate cells. Histopathologic evaluation of abnormal lung tissue revealed multiple, coalescing, densely cellular nodules composed of anaplastic and pleomorphic lymphocytes, with scattered binucleate and multinucleate cells. Marked infiltration and effacement of bronchiolar and vascular smooth muscle were present. These features are characteristic of lymphomatoid granulomatosis. To the authors' knowledge, this is the first report of pulmonary lymphomatoid granulomatosis in a cat.     

Cranial vena caval thrombosis secondary to invasive mediastinal lymphosarcoma in a cat

A 12-year-old female cat was diagnosed with a cranial vena caval thrombosis in association with a mediastinal lymphosarcoma. The cause of the cranial vena caval thrombosis was thought to be invasion of the venous wall by neoplastic lymphoid cells. Clinical signs of cranial vena caval thrombosis, such as swelling and oedema of the submandibular area, the ventral part of the neck and the forelimbs, were related to a space-occupying mediastinal lymphosarcoma, which also induced respiratory distress and cyanosis. Non-selective angiocardiography demonstrated the occlusion of the cranial vena cava and abnormal venous collateral vessels feeding the heart which are accepted as the venographic hallmark of clinically overt cranial vena caval syndrome. At postmortem examination, an intracaval thrombus, 5 cm in length, was seen extending from the costocervical vein to the sulcus terminalis of the right atrium.     

Mediastinal lymphoma with complete atrioventricular block in a horse

A 15-year-old, neutered-male pony presented with a history of weight loss during 4 months. Clinical evaluation revealed severe bradycardia and complete atrioventricular block. At necropsy, a lobulated mass in the anterior mediastinum and moderate enlargement of the superficial cervical lymph nodes were observed. The vagus nerve and the brachiocephalic trunk were embedded in this anterior mediastinal tumor. Histologically, the mass was composed of sheets of neoplastic lymphoid cells expressing CD3, with a low mitotic rate. To the best of our knowledge, this is the first reported case of mediastinal lymphoma associated with complete atrioventricular block in horses.     

Metastatic synovial cell sarcoma in two cats

Synovial cell sarcoma (SCS) with metastasis to the regional lymph node was diagnosed in two cats. Synovial cell sarcomas are rare in cats and metastatic SCS has not previously been reported. In both cases, treatment consisted of limb amputation and adjuvant doxorubicin. Local tumour recurrence and pulmonary metastases were diagnosed in one cat 316 days postoperatively. This cat died of chronic renal failure 444 days after limb amputation. The second cat died of an acute pulmonary thromboembolism 41 days postoperatively without evidence of local tumour recurrence or metastatic disease.     

Lymphangiosarcoma in two cats

Lymphangiosarcoma is a malignant neoplasm of the lymphatic endothelium that is rare in cats. This report describes two cases of feline lymphangiosarcoma that originated in the distal limb, causing intractable lymphoedema and serosanguineous discharge with ecchymoses in local and distant sites. In association with the neoplasia, one cat had cortical bone lysis of multiple metacarpal bones of the affected limb and the other had severe immune-mediated haemolytic anaemia (IMHA). The disease in both cases affected young cats and progressed rapidly. Persistent distal limb lymphoedema with serosanguineous discharge is suggestive of lymphangiosarcoma especially when local or distal ecchymoses are evident.     

Patent ductus arteriosus with pulmonary hypertension in a cat

Patent ductus arteriosus with pulmonary hypertension and right to left shunting of blood flow was diagnosed in a 9-month-old female cat. Because of the pulmonary hypertension, the cat did not have typical signs of patent ductus arteriosus; thus, cardiac angiography and catheterization were utilized to confirm the diagnosis. The patent duct was successfully occluded with a vascular clip.     

Pulmonary intravascular hemangiosarcoma in a cat

A 9-year-old, castrated male Japanese domestic cat presented with a complaint of exertional dyspnea. Based on the radiographic findings, presumptive diagnosis of aspiration pneumonia or primary diffuse pulmonary neoplasia in the right middle lobe was made. Histologically, the pulmonary lesion was characterized by diffuse thickening of alveolar wall with the proliferation of apparently atypical irregular-shaped cells. Immunohistochemical staining using anti-human factor VIII-related antigen antiserum showed positive reaction in the cytoplasm of the atypical cells. According to the findings, the lesion was diagnosed as pulmonary intravascular hemangiosarcoma.     

Extravasation injury associated with parenteral nutrition in a cat with presumptive gastrinomas

Objective – To describe the pathologic consequences of parenteral nutrition (PN) extravasation into the mediastinum of a cat. Case Summary – An 8‐year‐old domestic short hair cat with persistent vomiting and anorexia was initiated on PN for nutritional support. PN was being administered at a rate of 12.9 mL/h when inadvertent jugular catheter migration resulted in thrombophlebitis and cellulitis and 40–80 mL of PN extravasated into the SC and mediastinal tissues. The cat was euthanized 36 hours after the extravasation of PN due to poor prognosis related to the gastric complications associated with a presumed primary gastrinoma. Grossly there was excessive mediastinal lymphatic drainage and pronounced edema in the cervical SC and mediastinal tissue. Histopathologic examination of the PN‐extravasated area revealed a severe mixed inflammatory reaction, represented by a severe neutrophilic and mild histiocytic infiltrate with lymphoplasmacytic perivascular cuffing. No bacterial agents were observed or cultured from this area. Unique Information Provided – This is the first case report of a foreign body‐type reaction due to extravasation of PN (extravasation injury) in a cat. Extravasation of PN is not without pathologic consequence, and can result in a severe inflammatory reaction in affected tissues.     

CRANIAL MEDIASTINAL CYSTS IN NINE CATS

Nine cats, from 11 to 17 years of age (mean 13.6 years of age), were diagnosed with a cranial mediastinal cyst. Thoracic radiographs in all cats were characterized by an increased soft tissue opacity in the cranial mediastinum confirmed to be a cyst by ultrasonography or necropsy. Ultrasonographically cysts appeared as an anechoic mass. A low-cellularity clear fluid was obtained on aspiration. The majority of the cats (n = 8) presented for unrelated conditions with no signs of respiratory distress. No treatment for the cyst was pursued except for drainage during ultrasonographic-guided aspiration in several cats. On follow-up of eight cats, none were symptomatic for the cyst from 3-45 months after diagnosis. Mediastinal cyst should be considered when a cranial mediastinal mass is evident radiographically in an older cat. The majority of feline cranial mediastinal cysts are benign with no need for treatment.     

PERIPHERAL PULMONARY ARTERY STENOSIS IN A FOUR-MONTH-OLD WEST HIGHLAND WHITE TERRIER

A 4-month-old West Highland White Terrier was evaluated for dyspnea. Severe cardiac silhouette enlargement was present radiographically. Severe right ventricular hypertrophy and dilation with a dilated pulmonary trunk and a stenosis of the right pulmonary artery were diagnosed via echocardiography. Additional areas of peripheral pulmonary artery stenosis were diagnosed with nonselective computed tomography (CT) angiography and selective fluoroscopic angiography. Balloon dilation therapy was unsuccessful and the imaging findings were confirmed at necropsy.