L. Carrasco

Two Cases of Feline Visceral and Cutaneous Leishmaniosis in Spain

This paper describes clinical signs and lesions in two cases of leishmaniosis—one visceral and one cutaneous in the cat (Felis catus domesticus). The diagnosis was achieved by a combination of serology, light and electron microscopic studies. The vague nature of the clinical signs observed in both cases was particularly striking, and clinical features were similar to many other diseases commonly found in cats. Therefore, the use of various investigations to detect leishmaniosis (serum chemistry, serology and histopathology) is highly recommended in cases where clinical signs do not respond to conventional treatment.

Immunohistochemical Characterization of Hemangiopericytomas and Other Spindle Cell Tumors in the Dog

The immunohistochemical expression of muscle actin has been studied in 45 canine hemangiopericytomas (CHP) using a monoclonal antibody (HHF35) and formalin-fixed, paraffin-embedded specimens. The distribution of vimentin, desmin, cytokeratins, lysozyme, factor VIII-related antigen, S-100 protein, and glial fibrillary acidic protein was studied both in CHP and in some canine soft-tissue neoplasms (seven fibrosarcomas, seven benign schwannomas, seven benign fibrous histiocytomas, and six leiomyosarcomas) used as controls for differential diagnosis. All CHP and control tumors expressed vimentin. Twenty-three CHP expressed muscle actin, whereas all control tumors analyzed were muscle actin-negative, with the exception of leiomyosarcomas. Among muscle actin- and vimentin-positive CHP, one case could be reclassified as leiomyosarcoma because it was desmin-positive, two cases expressed lysozyme, and nine cases expressed S-100 protein. Among muscle actin-negative and vimentin-positive CHP, seven expressed S-100 protein. In addition, S-100 protein was detected in five schwannomas. All CHP and control tumors analyzed were negative for cytokeratins, factor VIII-related antigen, and glial fibrillary acidic protein. Our results support the hypothesis of a pericytic origin of CHP, and suggest that muscle actin, desmin, vimentin, and lysozyme could be useful for the differential diagnosis of canine spindle cell tumors, but not all these neoplasms can be identified with these tumor tissue markers.

Immunolocalization of the Smooth Muscle-Specific Protein Calponin in Complex and Mixed Tumors of the Mammary Gland of the Dog: Assessment of the Morphogenetic Role of the Myoepithelium

The immunohistochemical expression of the smooth muscle-specific protein calponin was studied to assess the contribution of myoepithelial cells to the histogenesis of spindle cells of complex and mixed tumors of the mammary gland of the dog and the origin of cartilage and bone in mixed tumors. Formalin-fixed tissues from 55 benign and malignant tumors (49 also containing surrounding normal mammary gland) were evaluated. Periacinar and periductal myoepithelial cells of all the 49 normal mammary glands were diffusely stained by the anti-human calponin monoclonal antibody. Calponin was found in 53 (98%) of the tumors studied, reacting with the myoepithelium-like cells of 86% of benign tumors and their remnants in 85% of malignant tumors. Five different types of calponin-immunoreactive myoepithelial cells were identified: hypertrophic myoepithelial cells, fusiform cells, stellate myoepithelial cells, rounded (myoepithelial) cells, and chondroblasts. Differences in staining intensity and staining pattern among these five types of cells suggested a transition of myoepithelial cells to chondroblasts. Stromal myofibroblasts also showed calponin immunoreactivity, but they did not react with a cytokeratin 14 monoclonal antibody, which recognizes myoepithelial cells in mammary gland. Calponin appears to be a very sensitive marker of normal and neoplastic myoepithelium in the canine mammary gland, and its identification in different cell types of complex and mixed tumors of the mammary gland of the dog suggests a major histogenetic role for myoepithelial cells.

Immunohistochemical Distribution Pattern of Intermediate Filament Proteins in 50 Feline Neoplasms

Twenty-eight epithelial and 22 nonepithelial feline tumors were studied immunohistochemically. Epithelial tumors were 10 squamous cell carcinomas, two basal cell tumors, two sebaceous gland carcinomas, three apocrine gland carcinomas, three thyroid papillary carcinomas, one thyroid solid carcinoma, one renal clear cell carcinoma, one renal papillary carcinoma, one endometrial carcinoma, and four lung bronchioloalveolar carcinomas. Nonepithelial tumors were 10 fibrosarcomas, one liposarcoma, one leiomyosarcoma, one rhabdomyosarcoma, one hemangiosarcoma, two mast cell tumors, one osteosarcoma, three melanomas, and two lymphomas. Commercially available antibodies directed against high- and low-molecular-weight keratins (keratin, RCK-102, NCL-5D3), vimentin, desmin, glial fibrillary acidic protein (GFAP), and neurofilament intermediate filament (IF) proteins were used in the avidin—biotin–peroxidase complex technique on formalin-fixed, paraffin-embedded tumor tissue samples. All epithelial tumors except the endometrial carcinoma expressed some type of keratin protein. Squamous cell carcinomas expressed high-molecular-weight keratins exclusively. Coexpression of high- and low-molecular-weight keratins was observed in one basal cell tumor, sebaceous and apocrine adenocarcinomas, and thyroid, renal, and lung carcinomas. In addition to keratins, vimentin immunoreactivity was found in all basal cell tumors, all sebaceous gland, thyroid papillary, renal, and lung adenocarcinomas, and one of the apocrine gland adenocarcinomas. Immunoreactivity with GFAP antibody was found in one basal cell tumor and one sebaceous gland adenocarcinoma. The endometrial carcinoma did not react with any of the antibodies applied. Nonepithelial tumors analyzed expressed either vimentin (fibrosarcomas, liposarcoma, haemangiosarcoma, mast cell tumors, osteosarcomas, melanomas) or vimentin and desmin (leiomyosarcoma, rhabdomyosarcoma, one fibrosarcoma) IF proteins exclusively. Lymphomas did not react with any of the antibodies employed. These findings indicate that IF proteins antibodies can be included in diagnostic panels of antibodies for immunocharacterization of feline tumors. In addition, they can be used as a basis for the diagnoses of poorly differentiated or undifferentiated feline neoplasms.

Outbreak of salmonellosis in farmed European wild boars (Sus scrofa ferus)

SALMONELLOSIS is a relatively common disease of swine that has been studied extensively. There is a zoonotic potential via infected pork products, and salmonellosis also causes important losses in feeder pigs (Schwartz 1991). In wild boars (Sus scrofaferus), Salmonella species have been isolated in two of 93 animals examined for meat inspection (Kanai and others 1997), but the dinical disease has not been reported. In recent years, farms of wild boars have been formed in Spain, to obtain adult animals for the repopulation of hunting areas. Since these wild boars are farmed in a semi-extensive manner similar to that used for Iberian and Duroc pigs, it is expected that they will suffer from diseases similar to those of domestic pigs. The aim of this study was to describe the clinical signs and gross and histopathological changes of an outbreak of salmonellosis in farmed wild boars. Since wild boars are hunted and their meat products are used for human food in many areas, the recognition of lesions caused by Salmonella species in these boars is of importance with regard to meat inspection. A farm, located in south Spain, comprised 200 wild boars of different ages, allocated in three farmyards of 30 to 40 hectares each. The animals were fed with grass, acorns and pellets, and drinking water was available in pools of stagnant water in which the wild boars could also take mud baths. Clinical signs of disease were present only in twoto fivemonth-old feeder animals, all from the same farmyard. The most common signs were progressive weight loss, anorexia, weakness, difficulties in walking, lethargy and death within three to five days after the onset of signs of the disease. Some animals, particularly those aged four to five months, died suddenly without signs of illness. Twenty animals died as a consequence of the disease. The most common gross lesions seen were ulcerative ileitis, typhlitis and colitis. The ulcers were circular or linear and were covered by fibrinous or black material (Fig 1). Petechial haemorrhages were frequently seen in the endocardium, epicardium, kidney, intestinal serosa, lung and liver. In four animals, numerous small yellowish foci were observed in the liver. Spleens were moderately enlarged and firm in all cases, except one that showed marked enlargement and a dark colour. The lymph nodes, especially mesenteric nodes, were enlarged and presented with subcapsular and medullary haemorrhages. Cranial and caudal lobes of the lung were plum-red and firm. The most common histopathological changes consisted of focal haemorrhages and microthrombi in capillaries and venules of internal organs. Ulcerative typhlocolitis and ileitis with typical button ulcers (Fig 2) were found in the majority of animals. The livers were congested and, in most cases, contained multiple necrotic foci located either in hepatic lobules or in portal spaces. In some cases, these foci had been infiltrated by small numbers of neutrophils, whereas others contained numerous macrophages and some lymphocytes. Similar necrotic foci with sparse neutrophilic infiltrate were found in the spleen of three animals. Lymph nodes and tonsils contained focal haemorrhages but lymphoid depletion was not seen. Lung lesions comprised mild to moderate alveolar oedema and an infiltrate of macrophages and lymphocytes in the interalveolar septi. The central nervous system was hyperaemic and isolated focal haemorrhages and thrombi were observed. Bacteriological culture of stomach and intestine contents, liver, spleen, lung and kidney produced bacterial colonies, which were identified, using biochemical and serological tests, as Salmonella choleraesuis (profile 6:7:C:1-5). An avidinbiotin-peroxidase immunohistochemical technique to detect hog cholera viral antigens (Martin de las Mulas and others 1997) was used on histological sections of spleen, lymph nodes, tonsils, liver, lung, kidney and brain from all necropsied wild boars. The results were negative. The clinical signs and gross and histopathological lesions of the affected wild boars in this study were similar to those reported in domestic pigs suffering from the septicaemic form of salmonellosis (Jones and Hunt 1983, Reed and others 1986). However, hyperaemic or cyanotic ears, tails and abdomen, often reported in domestic pigs (Wilcock 1986, Schwartz 1991, Barker and others 1993),were not found. This

Malignant schwannoma in a red deer (Cervus elaphus)

A five-year-old female red deer (Cervus elaphus) was in poor condition and severely lame on the left hindleg owing to a 19.4 cm x 15.9 cm mass involving and destroying the distal end (head) of metatarsal bones III and IV, the proximal sesamoid bones and the first phalanges (III and IV). The histopathological analysis revealed a spindle cell tumour with frequent palisade arrangement (Antoni type A pattern), and with highly anaplastic tumour cells in some areas. Structures resembling peripheral nerves were identified within the tumour. The neoplastic cells reacted with vimentin in a cytoplasmic pattern, and almost all of them reacted with S-100 protein in a nuclear and cytoplasmic pattern and did not express neurofilament, glial fibrillary acidic protein or keratins. This immunophenotype and the histopathological features were consistent with a diagnostic of malignant schwannoma. It was atypical because of the species affected, the location and the local malignancy.

Nasal zygomycosis and pulmonary aspergillosis in an American bison

Concomitant nasal zygomycosis and pulmonary aspergillosis was diagnosed in a 3-mo-old female American bison calf (Bison bison) in Pennsylvania (USA). Etiologic diagnosis was made by immunohistochemistry using a panel of monoclonal antibodies and heterologously absorbed polyclonal antibodies. In the lungs fungal infection was accompanied by hemorrhage, fibrin exudation, and infiltration with neutrophils. Fungi were observed to penetrate apparently normal epithelial lining of the nasal turbinates, and there was hemorrhage, edema, and invasion of blood vessels in the submucosa. In vessels fungi were typically associated with thrombosis. The calf may have been infected due to a high level of exposure to mouldy feed and litter in the environment in combination with a collapse of its natural defence mechanisms.

Intestinal smooth muscle hyperplasia in a goat.

Intestinal smooth muscle hypertrophy has been reported in natural form in horses, 4 pigs, 0 and humans 3 and experimentally in rats ,6,1 2 and guinea pigs. Hypertrophy is classified as primary or idiopathic when no predisposing lesion such as overload or distension is found at necropsy, and it has been related to an anomaly of the autonomic nervous system at the level of the small intestine, resulting in uncontrolled propulsive contractions of the small intestine. ,7 Secondary hypertrophy is appears following stenosis or partial obstruction of the intestinal lumen due to internal or external agents. 6,1 5 Intestinal smooth muscle hyperplasia has been reported in mammals only as a result of experimental infection by oral administration of Trichinella spiralis larvae in rats. 1 In birds, a natural case of intestinal smooth muscle hyperplasia has been reported in an American rhea, where it was associated with the presence of multiple diverticula in the intestinal mucosa. This paper is the first report of naturally occurring hyperplasia of the smooth muscle of the small intestine in a goat. A 4-year-old goat from a semiextensive farm displayed a fall in milk yield coinciding with various episodes of intermittent diarrhea over a 4-month period. At the end of this time, the goat was in a very poor state of health, with edema in ventral areas and advanced cachexia. One day prior to its death, the goat was depressed, recumbent, and suffering constant diarrhea. The carcass was referred to our laboratory with a tentative diagnosis of paratuberculosis because of the chronic nature of the disorder and the symptoms already described. Postmortem examination revealed cachexia and marked dehydration. At necropsy, subcutaneous edema was observed in the neck and the ventral region and ascites in the abdominal cavity. The main lesion was located in the small intestine. The duodenum and ileum were grossly normal, but a 1 5 cm segment of the jejunum was thickened, with an extremely swollen wall, reaching a diameter of 1 8.5 mm. The mucosa was 1 .2 mm thick and was edematous in appearance. The intestinal muscle wall was thickened to an average 2 .2 mm, and the serosa was dilated to 4.5 mm (Fig. 1 ). The remainder of the alimentary tract appeared slightly distended, and the lumen contained a certain amount of brown semisolid matter. Mesenteric lymph nodes showed no increase in size. Mesenteric fat adjacent to the affected segment of the jejunum contained several whitish nodules, which were firm and ranged from 0.5 to 2 cm in diameter. Tissue samples for light microscopy were routinely processed, fixed in 1 0% formalin, and embedded in paraffin. Sections 4 m thick were stained with hematoxylin and eosin

Fibrillary Astrocytoma in a Goat: Pathologic, Immunohistochemical, and Ultrastructural Study

Astrocytoma is 1 of the most common central nervous system tumors of domestic animals, having been reported in dogs (especially brachycephalic breeds), cats, pigs and cattle. ,2 ,5 Neither the international classification of nervous system tumo rs o f do mes tic animals 2 no r mo re re c ent publications mention the occurrence of this type of tumor in goats. In this paper, we describe the clinical, pathologic, immunohistochemical, and ultrastructural features of an astrocytoma in a goat. A 2 -year-old cross-bred (malagueaea x papoya) goat presented for circling and progressive blindness. Although the herd had been treated with albendazole 1 month prior to the appearance of symptoms, the presence of Oestrus ovis larvae was suspected, and the animal received ivermectin. Because the condition of the animal did not improve and complete blindness prevented the animal from feeding, euthanasia and necropsy were performed. After postmortem examination, tissue samples from different organs and tissues were fixed in 1 0% buffered formalin and embedded in paraffin. Four-micrometer-thick sections were stained with hematoxilyn and eosin (HE), and the avidin-biotin peroxidase complex (ABC) technique was applied for the demonstration of glial fibrillary acidic protein (GFAP), neurofilament proteins, vimentin desmin and keratin intermediate filament proteins, and the alpha and beta subunits of S 1 00 protein. All antibodies were diluted in 1 0% normal goat serum in phosphate-buffered saline (PBS) as follows: GFAP, vimentin, desmin, and keratin, 1 :200; neurofilament proteins, 1 :20; and S 1 00 protein subunits, 1 :500 each. Predigestion of tissue sections with 0.1 % pronase in PBS for 1 0 minutes at room temperature was used with S 1 00 protein subunit antibodies exclusively. Tissue samples of normal goat skin, tendon, spinal cord, skeletal muscle, small intestine, and brain tissue adjacent to the tumor were used as controls. The substitution of the specific reagents by PBS was used as a negative control in every assay. For electron microscopy, tissues were fixed in formalin and postfixed with 1 % osmium tetroxide, samples were embedded in Epon 81 2 , and 50-nm-thick sections were stained with uranyl acetate and lead citrate. At postmortem examination revealed a 4x 6x 3 .5-cm suprasellar and protruding mass immediately anterior to the pituitary gland that displaced and compressed the optic chiasm and nerves. The surface of the tumor was lobulated and indistinguishable from the adjacent nervous tissue. The cut surfaces were soft, gray, and homogeneous (Fig. 1 ). The tumor appeared circumscribed in most places, but focal infiltration of the hypothalamic and chiasmatic regions was seen.