Triphasic nephroblastoma in a horse.

A large abdominal mass in a 3-year-old filly was discovered clinically and removed and examined after the horse had been humanely killed. Histologically, three different tissue types were noted, occurring in equal amounts: epithelium largely in the form of well-differentiated tubules, multifocally distributed cell-dense foci of blastema, and myxoid to fibrous stroma. A diagnosis of triphasic nephroblastoma, a rare tumour in the horse, was made on the basis of microscopical findings. The finding of numerous glomeruloid structures confirmed the diagnosis and assisted in distinguishing the tumour from a teratoma. The histogenesis of nephroblastoma is briefly discussed in the context of the histological and immunohistochemical findings of the case.

Hepatic ultrasonography and pathological findings in dogs with hepatocutaneous syndrome: new concepts.

In dogs, hepatocutaneous syndrome (superficial necrolytic dermatitis) belongs to a group of syndromes in which cutaneous signs signal the presence of systemic disease. It is characterized by parakeratosis, superficial necrolysis, and basilar hyperplasia of the epidermis, in association with an unusual hepatopathy accompanied by certain metabolic derangements. Hepatocutaneous syndrome was diagnosed in 3 dogs on the basis of typical dermatologic changes and clinicopathologic findings. Hepatic ultrasonography revealed a hyperechoic network surrounding hypoechoic areas of parenchyma, resulting in a Swiss cheese-like appearance. The ultrasonographic image corresponded to the pathological findings. The liver had a nodular appearance, both grossly and microscopically; this was attributed to collapse of the areas of parenchyma surrounding the nodules, rather than to the cirrhosis and/or nodular hyperplasia reported previously.

Immunophenotypic classification of canine malignant lymphoma on formalin-mixed paraffin wax-embedded tissue by means of CD3 and CD79a cell markers.

Canine malignant lymphoma (CML) is a common lymphoid tumour. Identification of the immunophenotype is of prognostic importance: T-cell lymphomas have a worse prognosis than B-cell lymphomas. Until recently, identification of T- or B-cell lymphomas was undertaken by means of flow cytometry or fluorescent immunocytochemistry on frozen sections. Whilst valid in the research field, these methods are impractical for routine diagnostic histopathology in CML. Commercially available CD3 antibody has been successfully employed in T-cell identification in dogs in formalin-fixed paraffin wax-embedded tissue sections, but the lack of a B-cell marker has been a hindrance until the recent introduction of a commercially available pan-B cell marker, CD79a (DAKO M7051), suitable for diagnostic application upon formalin-fixed paraffin wax-embedded material. Antibody markers to CD3 and CD79a show cross-reactivity across species lines for B cells and T cells respectively. In this group of five selected canine cases, two were identified as B-cell and the other three as T-cell lymphoma, by means of CD3 and CD79a. To the best of our knowledge application of CD79a in cases of CML has not been reported.

Ulcerative pododermatitis in free-ranging African elephant (Loxodonta africana) in the Kruger National Park.

The occurrence of severe lameness in adult African elephant bulls in a shrub Mopane (Colophospermum mopane) ecosystem was investigated. Large ulcers in the soles of at least one front foot were seen in each of the recorded cases. Microscopically, the lesion can be described as a severe, chronic-active, ulcerative, bacterial pododermatitis (complicated by hypersensitivity/septic vasculitis). A variety of bacteria were isolated from these lesions as well as from regional lymph nodes. Streptococcus agalactiae was the most consistent isolate, while Dichelobacter nodosus, the only organism known to be involved with foot disease in domestic ruminants, was isolated from two cases. Contributory factors such as body mass, portal of entry and origin of potential pathogens may have predisposed to the development of the lesions.

Pathological findings in a natural outbreak of aflatoxicosis in dogs.

The gross and histopathological lesions of 10 cases in a natural outbreak of aflatoxicosis amongst dogs in the Republic of South Africa are reported. The 10 cases were classified as acute (1 case), subacute (7 cases) and chronic (2 cases) on the basis of the nature, degree and extent of the following histopathological fractures: hepatocellular fatty degeneration, necrosis or regeneration; proliferation of bile ductules; accumulation of bile within the canaliculi; fibroplasia; and, mucoid degeneration, necrosis or segmental atrophy of the larger intrahepatic bile ducts. Fatty degeneration was noted grossly in the livers of all 10 cases and bile stasis in 4. Varying degrees of fibrosis were present depending on the stage of the disease. In the 2 chronic cases in which nodular regeneration was also observed fibrosis was pronounced. Other macroscopic findings included icterus, anaemia, ascites, hydrothorax, hydropericardium, anasarca, pulmonary oedema, gastro-enterorrhagia and nephrosis.

Renal dysplasia in two adult horses: clinical and pathological aspects.

Renal dysplasia is reported in two adult horses in chronic renal failure. Renal dysplasia, complicated by severe interstitial pyelonephritis, was diagnosed on renal biopsy and confirmed on post mortem examination.

Lymphangiomatosis of the pelvic limb in a Maltese dog.

A case of lymphangiomatosis is described affecting the right pelvic limb of an 18-month-old, female Maltese dog. A progressive swelling around the stifle had developed subsequent to a routine tibial crest transposition. The swollen area eventually progressed to involve the entire limb circumferentially, to end abruptly in the mid-metatarsal region. The skin of the affected area was deep red in colour, devoid of hair, and had numerous large, thin-walled vesicles that were easily ruptured and from which a serosanguineous fluid exuded. The swelling pitted on digital pressure and showed fluctuant mobility. The microscopic appearance of biopsied and post mortem material mimicked that of lymphangioma. However, the signalment, clinical presentation and histological features are consistent with a diagnosis of the recently reported variant of human lymphangiomatosis, lymphangiomatosis of the limb.

The pathology of pulmonary aspergillosis in a piglet.

The pathology of pulmonary aspergillosis in a piglet is described. The dominant feature is the pneumonic process which is acute, focal, disseminated and necrotising to purulent in character. Fungal hyphae typical of the aspergilli are present within the lesions. The comparative aspects of this case and the primary invasive form of pulmonary aspergillosis in man are briefly enunciated.

Cerebellar cortical atrophy in a puppy.

A description is given of the history and neuropathology of a mongrel puppy which had suffered from cerebellar cortical atrophy. The condition was attended by intractable cerebellar ataxia and characterised by selective degeneration of the Purkinje cells of the cerebellar cortex. Cerebellar dysfunction is briefly reviewed. The lesion and possible aetiology are briefly discussed.

The pathology of a case of biliary atresia in a foal.

The pathological features of biliary atresia in a foal are described. A 4-week-old American Saddler foal was presented for autopsy following an illness characterised by clinical features indicative of hepatic failure. The significant macroscopical lesions occurred in the liver which was extremely enlarged, mottled in appearance and indurated. Bile stasis was evident. Lobular distinction was absent and on sectioning, large bile ducts were absent. A moderate ascites, hydrothorax and hydropericardium and a mild anasarca and intermuscular oedema accompanied the hepatic lesion. The diagnosis of biliary atresia was determined by the histopathological features of bile duct proliferation and extensive replacement fibrosis. The condition is compared to extrahepatic and intrahepatic biliary atresia of man and evidence is presented for regarding this case to be one of extrahepatic origin.

The pathology of a case of biliary atresia in a foal.

The pathological features of biliary atresia in a foal are described. A 4-week-old American Saddler foal was presented for autopsy following an illness characterised by clinical features indicative of hepatic failure. The significant macroscopical lesions occurred in the liver which was extremely enlarged, mottled in appearance and indurated. Bile stasis was evident. Lobular distinction was absent and on sectioning, large bile ducts were absent. A moderate ascites, hydrothorax and hydropericardium and a mild anasarca and intermuscular oedema accompanied the hepatic lesion. The diagnosis of biliary atresia was determined by the histo-pathological features of bile duct proliferation and extensive replacement fibrosis. The condition is compared to extrahepatic and intrahepatic biliary atresia of man and evidence is presented for regarding this case to be one of extrahepatic origin.

Salmonellosis in an adult dairy cow.

An outbreak of diarrhoea occurred in a Jersey herd after the introduction of new stock. One of the cows was examined and treated unsuccessfully. Clinical findings included depression, fever, dehydration, congestion, signs of colic and a severe diarrhoea. The post mortem examination revealed emaciation, pseudomembranous enteritis, mesenteric lymphadenopathy and focal disseminated hepatic necrosis. Salmonella typhimurium was isolated from the faeces, mesenteric lymph nodes and liver.

Fatal acute babesiosis in a juvenile wild dog (Lycaon pictus).

Clinical examination of a 75-day-old captive juvenile wild dog suffering from lassitude revealed pale mucous membranes, icterus, laboured respiration, a "water-hammer" pulse and splenomegaly. A peripheral blood smear containing numerous Babesia-infected erythrocytes confirmed the diagnosis of babesiosis. Treatment was unsuccessful and the animal died shortly after receiving a blood transfusion. The findings at necropsy were typical for acute babesiosis and included anaemia, icterus, splenomegaly and haemoglobinuria. In addition, marked atrophy of the thymus and lymph nodes was evident. Microscopic and electron microscopic examination of selected tissues disclosed high parasitaemia with vascular stasis and injury to both endothelial and parenchymal components. It is speculated that vaccination-induced immune incompetence predisposed to development of clinical babesiosis.

Malignant mesothelioma in a seven-week-old puppy.

A case of diffuse malignant peritoneal mesothelioma in a 7-week-old puppy is reported. The puppy presented with a recurrent abdominal effusion. An exploratory laparotomy revealed extensive adhesions. Necropsy findings included pleural thickening, and enlargement of the renal and anterior mediastinal lymph nodes. The microscopic features were typical of primary desmoplastic diffuse mesothelioma of the peritoneum and pleura with secondary lymph node metastasis (renal and anterior mediastinal). The tumour was classified as epithelial in type. The extent of the tumour and the distant metastasis were considered to reflect a high degree of malignancy. A congenital origin was suspected.

Spinal nephroblastoma in an Irish wolfhound.

A 1-year-old Irish wolfhound was presented with a history of slowly progressive left pelvic limb paresis. A neurological examination demonstrated bilateral deficits referable to the thoracolumbar spinal cord. Lumbar cerebrospinal fluid contained neoplastic cells. An intradural, extramedullary mass was demonstrated by myelography at the caudal aspect of T13. Surgical excision was abandoned owing to severe macroscopic damage to, and apparent infiltration of, the cord, and the dog was euthanased. The tumour was diagnosed histologically as an extrarenal nephroblastoma. Nephroblastoma should be suspected in young, large-breed dogs with intradural extramedullary masses over spinal segments T10-L2. The prognosis for complete recovery after surgical excision is guarded to poor.

The comparative role of haemoglobinaemia and hypoxia in the development of canine babesial nephropathy.

Renal pathology associated with haemoglobinaemia resulting from Babesia canis infection is ascribed to haemoglobinuria, with or without a contribution from anaemic hypoxia. This study was undertaken to investigate the relative roles of haemoglobinaemia and hypoxia in renal function and pathology in the dog. Three groups of 6 dogs each were used over a 4-day period. The dogs in the 1st group were infused with homologous canine haemoglobin, anaemic hypoxia was induced in the 2nd group, and both treatments were applied in the 3rd group. Full urinalyses, serum urea and creatinine concentrations, fractional clearance of sodium and the activity of urine enzymes, were assessed daily. At the end of the trial period, the glomerular filtration rate (GFR) was determined and kidney specimens collected for light and electron microscopy. In the group with hypoxia only, the urine sediment contained more casts and a greater number of renal tubular epithelial (RTE) cells than in either of the other groups. Hypoxia resulted in greater enzymuria, suggestive of RTE cell pathology, whereas haemoglobinuria did not appear to have any effect on urine enzyme activity. Hypoxia resulted in a decreased GFR. Histological examination revealed a mild, single-cell tubular necrosis in the majority of the animals (all 3 groups), with granular casts in the hypoxic groups. There appeared to be a large individual variation in the ability of the kidney to handle infused haemoglobin. It was concluded that severe haemoglobinaemia did not induce a significant nephropathy, anaemic hypoxia appeared to cause a very mild nephropathy, and the combination of haemoglobinaemia and anaemic hypoxia did not exacerbate this change. These lesions were very different from those described in canine babesiosis.

Accidental pentobarbital poisoning in a lioness.

A lioness was accidentally poisoned by consumption of meat of a horse euthanased with pentobarbital. The post mortem examination was negative but thin-layer gas-chromatographic and mass-spectrometric methods revealed a pentobarbitone concentration of 1, 14 mg kg-1 in the chloroform extracts of the liver of the animal.

Renal pathology in working dogs in the South African National Defence Force.

Urine analysis, serum biochemical profile and a cortical wedge biopsy for histopathological examination was performed on 42 South African National Defence Force (SANDF) dogs from around the country. The only significant finding on urine analysis and serum biochemistry was a relatively large number (16/42) of dogs with elevated serum inorganic phosphate levels. Histopathology revealed that only 9 of the animals had normal kidneys reflected in the wedge biopsy material, with over 50% of them showing signs of glomerular pathology (primarily mesangioproliferative glomerulonephritis). Other conditions detected histopathologically were haemosiderosis (47% of animals), focal nephrosis (2.4%), membranoproliferative glomerulonephritis (2.4%), focal interstitial nephritis (4.7%) and acute tubular nephrosis (4.7%). The lesions observed were of limited distribution and extent; this histopathological finding may account for the absence of significant abnormalities on urine analysis or serum biochemistry profiles. It appears from these results that a large percentage of the SANDF population would be expected to have mild renal lesions, but that these lesions are not severe enough to lead to clinical signs. The findings of this study are similar to those of randomly selected populations of non-military dogs performed in other areas of the world, which also demonstrated an unexpectedly high incidence of histopathological renal pathology in dogs considered healthy. These lesions may well, however, play a role in later life, and it is recommended that military veterinarians maintain an index of suspicion for renal disease, particularly glomerular disease. The aetiology of the histopathological lesions is unknown.

Spastic paresis in two littermate pups caused by Toxoplasma gondii.

The clinical and pathological findings in 2 sibling Bloodhound pups with spastic paresis of the pelvic limbs due to toxoplasmosis are described. Macropathology consisted of bilateral atrophy of the musculature of the affected limbs. Histopathology revealed meningo-encephalitis involving the cerebellum and medulla oblongata, diffuse meningomyelitis, radiculoneuritis of the lumbar spinal nerves and polymyositis and atrophy of skeletal muscle. Epizootological investigations failed to determine the source of the infection. Dissemination of the infection by a route other than the haematogenous pathway is considered and discussed.

Pox virus infection in captive juvenile caimans (Caiman crocodilus fuscus) in South Africa.

Light grey macules developed on the skin and in the mouths of juvenile caimans, (Caiman crocodilus fuscus) (n = 8), kept in the quarantine section of the reptile park at the National Zoological Gardens, Pretoria, Republic of South Africa. The gross, histopathological and ultrastructural features of the lesions were commensurate with pox virus infection. This outbreak closely resembled the disease described elsewhere in 3 juvenile captive caimans.