Two cases of dermatophytic pseudomycetoma in the dog: an immunohistochemical study

Two cases of canine dermatophytic pseudomycetoma resulting in subcutaneous nodules resembling those previously reported in Persian cats are described. Culture performed from one nodule yielded dark yellow colonies consistent with Microsporum canis. Immunohistochemistry, using rabbit anti-M. canis, demonstrated specific binding to fungal elements in paraffin sections. The specificity of the antiserum was further tested by an agar gel immunodiffusion assay using a soluble extract from a feline isolate of M. canis as antigen. The antiserum did not cross-react with an Aspergillus fumigatus antigen. These are the first two reported cases of canine dermatophytic pseudomycetoma and immunohistochemical staining supported the diagnosis.     

Gastrointestinal stromal tumors of the equine cecum

Ten cecal tumors were identified during the postmortem examination of seven horse carcasses at slaughter (one horse had three tumors). The multinodular and hemorrhagic tumors ranged from 1 to 10 cm in diameter and consisted of spindle cells arranged in thin, interconnected trabeculae that were often separated by sinuses filled with mucinous fluid, erythrocytes, and siderophages. Spindle cells of all tumors were immunopositive for vimentin, neuron-specific enolase, and c-kit protein but lacked reactivity with antibodies to glial fibrillary acidic protein, S100 protein, and desmin. In one tumor, spindle cells diffusely bound antibodies to synaptophysin. Most tumors contained focal reactivity to smooth muscle actin antibodies; one tumor reacted diffusely. Ultrastructurally, tumor cells were connected by desmosome-like structures and exhibited extended cell processes; some contained dense core neurosecretory granules. These equine stromal tumors appeared to share some characteristics with human gastrointestinal stromal tumors.     

Morphologic, immunohistochemical, and molecular characterization of hepatosplenic T-cell lymphoma in a dog

A 13-year-old neutered male Jack Russell Terrier (Parson Russell Terrier) was presented to the Texas Veterinary Medical Center with a history of lethargy, depression, vomiting, and fever. The dog had mildly regenerative anemia, severe thrombocytopenia and low antithrombin activity. Marked splenomegaly was found on physical examination and imaging studies, and malignant round cell neoplasia and marked extramedullary hematopoiesis were diagnosed on aspirates of the spleen. The dog underwent exploratory laporatomy and splenectomy. Because of a rapid decline in clinical condition postsurgery, the dog was euthanized. Splenic and hepatic biopsies were submitted for histopathologic evaluation. A neoplastic population of round cells was found throughout the splenic parenchyma and within hepatic sinusoids. The neoplastic cells stained strongly positive for CD3 (T-cell marker) and were negative for CD79a (B-cell marker) and lysozyme (histiocytic marker). A diagnosis of T-cell lymphoma was confirmed by assessment of T-cell clonality using canine-specific polymerase chain reaction-based techniques. Although expression of the gammadelta T-cell receptor was not evaluated, this case shares many similarities with a rare syndrome in humans known as hepatosplenic gammadelta T-cell lymphoma.     

Listeric meningoencephalomyelitis in a cougar (Felis concolor): characterization by histopathologic, immunohistochemical, and molecular methods

Listeria monocytogenes has been recognized as an important food-borne pathogen in animals. Records of the disease caused by this bacterium in large felids are, however, rare. The nervous form of listeriosis was diagnosed in a 12-year-old male cougar (Felis concolor) with a several-day history of neurologic disease characterized by excess salivation, head pressing, and circling that progressed to recumbency and death. Microscopically, the main alteration in the brain and spinal cord was a variably severe meningoencephalomyelitis composed mainly of mononuclear cell aggregates with fewer neutrophils. L. monocytogenes was isolated from the brain by microbiological culture, and L. monocytogenes antigen was detected in formalin-fixed, paraffin-embedded sections of brain and spinal cord by immunohistochemical analysis. On the basis of the nucleotide sequence of the 16S rRNA gene, the isolated strain was determined to be serotype 1/2a. Food-borne transmission of the bacterium was suspected, but food was not available for testing.     

Partial carpal and pancarpal arthrodesis in the dog: a review of 50 cases

Fifty-six carpal arthrodeses were carried out in 50 dogs. Six of these had bilateral arthrodeses. A dynamic compression plate (DCP; Straumann Great Britain Ltd), placed on the dorsal aspect of the carpus, was used for fixation in all cases. The main indication for pancarpal arthrodesis was a hyperextension injury of the radiocarpal joint. Forty-three pancarpal arthrodeses were performed in 40 dogs (a bilateral procedure was performed in three). Hyperextension injuries of the intercarpal and carpometacarpal joints were treated by partial carpal arthrodesis in 10 dogs; three of these had bilateral procedures. Seventy-four per cent of dogs treated by pancarpal arthrodesis regained full limb function. Only 50 per cent of cases treated by partial carpal arthrodesis had a similar result.     

Olfactory neuroepithelioma in a dog: an immunohistochemical and electron microscopic study

A case of olfactory neuroepithelioma was investigated electron microscopically and immunohistochemically. The tumor mass was found in the nasal cavities of a 10-year-old female dog, which showed epistaxis, nasal discharge and facial swelling. The tumor tissue consisted of tubular structure of cuboidal to columnar cells and compactly arranged nests of small cells surrounded by a fibrovascular stroma. Mitotic figures were frequently observed. Immunohistochemically, the tumor cells frequently showed positive for neurofilament protein, synaptophysin and/or carnosine in addition to keratin. Ultrastructurally, tight junction was observed between the tumor cells. No dense-cored secretory granules were shown in the tumor cells. These findings indicated that the present tumor had neuronal and epithelial features probably originating from the olfactory epithelium.     

Clinical and immunohistochemical differentiation of gastrointestinal stromal tumors from leiomyosarcomas in dogs: 42 cases (1990-2003)

OBJECTIVE: To reexamine (via immunohistochemical techniques) canine tissue samples that had been previously classified as gastrointestinal leiomyosarcomas (GILMSs), identify and differentiate gastrointestinal stromal tumors (GISTs) from GILMSs, and compare the biological behavior and clinical course of GISTs and GILMSs in dogs. DESIGN: Retrospective case series. ANIMALS: 42 dogs. PROCEDURES: Medical records of 42 dogs for which a histologic diagnosis of GILMS was confirmed were reviewed for signalment, clinical signs, physical examination findings, results of initial diagnostic tests, surgical findings, adjunctive treatment, location of the tumor, completeness of resection, and outcome after surgery. Archived tumor tissue specimens from each dog were restained via immunohistochemical techniques to differentiate tumor types. Long-term follow-up information was obtained from the medical record or through telephone interviews with owners and referring veterinarians. RESULTS: On the basis of immunohistochemical findings, 28 of 42 tumors were reclassified as GISTs and 4 were reclassified as undifferentiated sarcomas; 10 tumors were GILMSs. In dogs, GISTs developed more frequently in the cecum and large intestine and GILMSs developed more frequently in the stomach and small intestine. Median survival times for dogs with GISTs and GILMSs were 11.6 and 7.8 months, respectively; if only dogs surviving the perioperative period were considered, median survival times were 37.4 and 7.8 months, respectively. These differences, however, were not significant. CONCLUSIONS AND CLINICAL RELEVANCE: In dogs, many previously diagnosed GILMSs should be reclassified as GISTs on the basis of results of immunohistochemical staining. The biological behavior of these tumors appears to be different.     

Hypercalcaemia in the dog: a study of 40 cases

Forty dogs referred to the University Department of Clinical Veterinary Medicine, Cambridge for medical and oncological conditions between 1985 and 1990 were found to be hypercalcaemia In 18 cases the primary or underlying condition was diagnosed as lymphoproliferative disease with multicentric lymphoma occurring most commonly. Ten dogs were suffering from hypoadrenocorticism (Addison's disease) and two had adenocarcinomas of the apocrine glands of the anal sac. In three dogs a clinical diagnosis of renal dysplasia was made, this diagnosis being confirmed at post mortem examination in one dog. In the remaining cases hypercalcaemia was associated with a primary lung tumour, a thymoma, an osteosarcoma with widespread skeletal metastases, primary hyperparathyroidism due to a parathyroid adenoma, chronic panniculitis, iatrogenic hypoadrenocorticism following mito-tane therapy (one case each] and, in a further case, no diagnosis was reached. The most common clinical signs were inappetence, polyuria/ polydipsia, weakness, vomiting, lethargy and depression. As a group, the dogs with lymphoproliferative disease had a significantly higher mean plasma calcium concentration (4-3 ± 0–7 vs 3–5 ± 0–4 mmol/litre), a significantly lower mean plasma inorganic phosphate concentration (1–5 ± 0–5 vs 2–4 ± 09 mmol/litre) and were significantly older (5-5 ± 2–4 vs 3-3 + 1–8 years) than the dogs with hypoadrenocorticism.     

A histopathologic and immunohistochemical review of archived UK caprine scrapie cases

In 2005, a prion disease identified in a goat from France was reported to be consistent with disease from the bovine spongiform encephalopathy (BSE) agent. Subsequent retrospective examination of UK goat scrapie cases led to the identification of one potentially similar, but as yet unconfirmed, case from Scotland. These findings strengthened concerns that small ruminant populations exposed to the BSE agent have become infected. The lack of data relating specifically to scrapie in goats has been contributory to past assumptions that, in general, sheep and goats respond similarly to prion infections. In this study, brain material from 22 archived caprine scrapie cases from the UK was reviewed by histopathology and by immunohistochemical examination for accumulations of disease-specific prion protein (PrP(Sc)) to provide additional data on the lesions of caprine scrapie and to identify any BSE-like features. The vacuolar change observed in the goats was characteristic of transmissible spongiform encephalopathies in general. PrP(Sc) immunohistochemical morphologic forms described in scrapie and experimental BSE infections of sheep were demonstrable in the goats, but these were generally more extensive and variable in PrP(Sc) accumulation. None of the cases examined showed a PrP(Sc) immunohistochemical pattern indicative of BSE.     

Malabsorption syndrome in the dog: a study of thirty-eight cases

The clinical findings and results of an investigational procedure on thirty-eight confirmed cases of canine malabsorption are described in detail. Exocrine pancreatic insufficiency was frequently responsible for the syndrome, but on occasions small intestinal disorders, liver disease and alactasia were diagnosed. Possible methods of treatment are suggested and their value in the present series of cases discussed briefly. Résumé. Les résultats cliniques et les résultats d'un procédé d'investigation concernant trente-huit cas confirmés de malabsorption canine, sont décrits en détail. L'insuffisance sécrétoire du pancréas en exocrine était fréquemment la cause responsable du syndrome, mais en certaines occasions, on a diagnostiqué de légers troubles intestinaux, une maladie de foie et une alactasie. On suggère des méthodes possibles de traitement et leur valeur dans la présente série des cas est brièvement discutée. Zusammenfassung. Die Abhandlung gibt eine eingehende Beschreibung der klinischen Befunde und die Ergebnisse einer Forschungsmethode an 38 nachgewiesenen Fällen von Malabsorption bei Hunden. Exokrine Pankreasinsuffizienz war dabei häufig für die Entstehung des Syndroms verantwortlich; jedoch wurden in einigen Fällen auch kleine Darmstörungen, Lebererkrankungen und Alaktasie diagnostiziert. Auf einige mögliche Behandlungsmethoden wird hingewiesen und deren Wirksamkeit im Rahmen der vorliegenden Serie wird kurz besprochen.     

Hypothyroidism in the dog: a retrospective study of sixteen cases

Sixteen dogs with confirmed hypothyroidism were reviewed. The diagnosis was based on subnormal plasma thyroxine concentration and poor response following TSH administration. Common clinical signs were alopecia (12 dogs), lethargy (11) and obesity (11). Plasma cholesterol concentrations were abnormally high in 10 of 14 cases tested, five of 12 were anaemic and three of five had increased creatine phosphokinase activity. Skin changes compatible with endocrinopathy were present in all five cases biopsied. Spontaneous muscle activity was found on electromyography in four cases so examined. All dogs were treated with sodium levothyroxine, and 10 of 13 for which information was available responded satisfactorily.     

Pleural endometriosis in an aged rhesus macaque (Macaca mulatta): a histopathologic and immunohistochemical study

Endometriosis is defined as the presence of endometrial tissue outside the uterine cavity and is one of the most common reproductive abnormalities encountered in women as well as Old World primates. The majority of endometriosis cases in Old World primates occur within the abdominal cavity, with spread to extraabdominal sites considered to be a rare event. A 19-year-old multiparous female rhesus macaque (Macaca mulatta) presented to necropsy for difficulty breathing and weight loss. Grossly, the animal had marked abdominal endometriosis and severe hemoabdomen and hemothorax, the latter of which was accompanied by marked pleural fibrosis. Histologic examination confirmed the abdominal endometriosis and also revealed numerous uterine glands and stroma embedded within the pleural fibrosis. Rafts of endometrial tissue were present within pulmonary lymphatics and the tracheobronchial lymph nodes. Immunohistochemically, all ectopic endometrial tissue had varying degrees of positive immunoreactivity to cytokeratin, vimentin, progesterone and estrogen receptors, and calretinin but was negative for desmin and carcinoembryonic antigen. Pleural endometriosis is an extremely rare manifestation of endometriosis in nonhuman primates. This case report emphasizes lymphatic spread as a likely mechanism for extrauterine endometriosis.     

Hepatobiliary neuroendocrine carcinoma in cats: a clinicopathologic, immunohistochemical, and ultrastructural study of 17 cases

Hepatobiliary neuroendocrine carcinoma was diagnosed in 17 cats in a period of 10 years. Seven tumors were of intrahepatic origin, one of which was a composite containing components of epithelial and neuroendocrine carcinoma. Nine tumors were of extrahepatic origin, and one tumor was located in the gall-bladder. The cats were adult and geriatric, and the male : female ratio varied according to tumor group. Hepatomegaly, anorexia, weight loss, and vomiting were the most common clinical signs observed in the cats with hepatic neuroendocrine carcinoma. The cats with extrahepatic neuroendocrine carcinoma showed these signs plus icterus (5/9) and high concentrations of hepatic enzymes. Histologically, the hepatic neuroendocrine carcinomas had two patterns, one with acinar structures separated by vascular stroma lined by cuboidal or columnar cells and the other solid with groups of anaplastic cells separated by vascular stroma. The composite tumor consisted of both bile duct carcinoma and neuroendocrine carcinoma. The extrahepatic neuroendocrine carcinomas and the gallbladder neuroendocrine carcinoma were characterized by solid sheets or groups of round to oval cells with vascular or fibrovascular stroma. Immunohistochemical examination of 10 of the neuroendocrine carcinomas revealed that all 10 stained with neuron-specific enolase; one bile duct carcinoma and the gallbladder carcinoma stained with chromogranin; four of five bile duct carcinomas and the gall bladder carcinoma stained with synaptophysin; and one bile duct carcinoma stained with gastrin. One cat with hepatic carcinoma had duodenal ulcer; in this cat, ultrastructural studies showed neurosecretory granules leading to the diagnosis of Zollinger-Ellison syndrome. In four cats in which necropsy was permitted, carcinomatosis (4/4), lymph nodes (4/4), lungs (2/4), and intestines (1/4) were the metastatic sites. Fourteen of the 17 cats were euthanatized during or immediately after surgery.     

Bicipital tendinitis and tenosynovitis in the dog: a study of 15 cases

AIM: To describe the clinical, radiographic, and sonographic features of 15 dogs with bicipital tendinitis and tenosynovitis, classify them according to cause, and evaluate the long-term efficacy of treatment. METHODS: Dogs exhibiting forelimb lameness with pain localised to the biceps tendon were included in the study. Sonographic examination of the tendon and tendon sheath, and radiographic examination including positive contrast arthrograms of the shoulder joint were performed, and assessed for features consistent with biceps tendon disease. In some cases, synovial-fluid analysis and surgical investigation were also undertaken. The causes of the conditions were classified as either traumatic, mechanical, neoplastic or inflammatory. Dogs were treated conservatively with rest and anti-inflammatory drugs, or surgically by either transection of the transverse humeral ligament or tenodesis of the biceps tendon. Assessment of the effects of treatment was made by re-examination at six weeks and from information gained by telephone interview with the dog's owner at longer-term follow-up. RESULTS: Bicipital tendinitis and tenosynovitis were common causes of forelimb lameness in active, middle-aged or older, medium to large-breed dogs. The most sensitive physical tests for localising pain to the biceps apparatus were shoulder flexion with the elbow extended, focal digital pressure applied directly to the biceps origin, and the biceps retraction test. Sonographic assessment was found to be more sensitive than shoulder radiography or arthrography for characterising the lesion. Conservative treatment of 11 traumatic cases resulted in good or excellent function at long-term follow-up. One mechanical bicipital tendinitis secondary to mineral deposits within the supraspinatus tendon improved following transection of the transverse humeral ligament and removal of the deposits. One of two cases of inflammatory tendinitis/ tenosynovitis improved following tenodesis. One dog with neoplastic disease did not improve and was euthanased. CONCLUSIONS: The diagnosis of bicipital tendinitis and tenosynovitis requires a careful examination using a combination of physical tests. Of the ancillary tests, sonography was the most reliable, however information gained from all tests was useful in fully evaluating the biceps apparatus and shoulder joint. The classification system employed in this study was helpful in selecting a treatment protocol and determining the likely prognosis.     

Gastrointestinal ultrasonography of the dog: a review of 265 cases (1996-1998)

The findings of ultrasonography of the gastrointestinal (GI) tract of 265 dogs with GI disorders were analysed retrospectively. The sonographic changes associated with various inflammatory and neoplastic conditions and mechanical obstruction of the GI system were recorded and discussed. Sonographic alterations of the pancreas and the tissues adjacent to the GI tract were also included in the study. Ultrasonographic alterations of the GI tract were classified into three main categories: thickening of the GI wall, changes in peristalsis and dilation of the lumen. Localised thickening of the GI wall with disruption of its structure was caused by both neoplastic diseases and by inflammatory disorders. However, diffuse thickening with retained wall structure was generally associated with inflammatory diseases. The criteria previously established for the ultrasonographic diagnosis of intestinal obstruction were successfully applied to a large number of GI disorders. Pancreatitis was most often associted with hyperchoic mesentery and hypoechoic pancreas mass, but similar alterations were encountered in some cases of gastric or duodenal ulceration. Except in cases of invaginations and intestinal obstructions, the observed ultrasonographic changes were not specific enough for a definitive diagnosis. Nevertheless, ultrasonography proved to be a valuable technique in the diagnostic process of GI disorders of the dog.     

Paranasal meningioma in the dog: a clinicopathologic study of ten cases

Paranasal meningiomas were diagnosed in ten dogs based on gross and light microscopic examinations of tissue specimens, and, in one case, electron microscopic examination. Seven of ten dogs were female (average age was 13 years). Most dogs (7/10) had seizures on examination. Two dogs with meningioma located in the nasal cavity had nasal discharge, and one had epistaxis. Tumors originated in the nasoparanasal region (eight) and frontal region of the cranial cavity (two). The histologic types of meningioma included psammomatous (two), transitional (three), meningotheliomatous (two), fibroblastic (two), and angioblastic (one). Tumors were malignant and extended to the brain in eight cases. These tumors differed from intracranial meningiomas mainly in their more anaplastic nature and aggressive behavior.     

Mammary cancer in the dog: a study of 120 cases.

Of the 120 cases of mammary cancer occurring in 117 female dogs (15 spayed), 2 male dogs, and 1 dog of undetermined sex, 107 (nearly 90%) were observed in dogs 8 to 15 years old. Mammary tumors occurred in nearly 14% of 875 female dogs with neoplasms. Nearly 60% of 128 neoplasms were located in the 4th and 5th mammary glands. Of the 128 cancers in these 120 dogs, 85 were classified as duct carcinoma, 38 as lobular carcinoma, 3 as malignant mixed tumor, and 2 as duct and lobular carcinomas. Most duct carcinomas originated in the epithelial cells of ducts at all levels, and a few arose in previously benign duct papillomas. The lobular carcinomas arose in alveoli and developed into progressively larger lobules. A negative factor in the development of mammary cancer is ovariectomy before or shortly after the first estrous cycle in the dog and before the age of 40 in women. In both dog and man, aging is a positive factor in the development of mammary cancer. In women, other positive factors are nulliparity and inheritance; e.g., a high rate of breast cancer in close female relatives of Jewish extraction. An epidemiologic study of breast cancer in man and dog in high-risk countries(e.g., United States) and low-risk countries (e.g., Japan) is indicated.     

Mesenteric volvulus in the dog: a retrospective study of 12 cases

Mesenteric volvulus was diagnosed in 12 dogs over a nine-year period. Each case was presented with abdominal distension and shock. Haematochezia, which is frequently reported in association with mesenteric volvulus, was present in only two of the dogs. The diagnosis, which in all cases was based on radiography, was followed by immediate treatment for shock and surgical intervention whenever possible. In five of the 12 cases, the volvulus was treated successfully and these patients survived. This indicates that the prognosis for mesenteric volvulus might be better than is currently believed, and immediate laparotomy is recommended if mesenteric volvulus is suspected.     

A histopathologic,immunohistochemical, and ultrastructural study of the intestine in pigs inoculated with classical swine fever virus

The aim of this study was to report on the lesions occurring in the intestine during experimental classical swine fever (CSF) and to clarify the nature of infected cells and the distribution of viral antigen. Thirty-two pigs were inoculated with the virulent CSF virus (CSFV) isolate Alfort 187 and slaughtered from 2 to 15 postinoculation days; four animals of similar background served as a control group. Immunohistochemistry, electron microscopy, and the transferase-mediated deoxyuridine triphosphate nick-end labeling method were used to detect viral antigens and apoptosis. The results showed progressive lymphoid depletion and mucosal necrosis. The lymphoid depletion could have been caused by apoptosis of lymphocytes but could not be directly attributed to the effect of CSFV on these cells. Vascular changes, pathogenic bacteria, and viral infection of epithelial cells were ruled out as causes of necrotic lesions. However, large virally infected monocytes-macrophages with ultrastructural changes indicative of activation were observed in the intestine. This suggests that monocytes-macrophages play an important role in the pathogenesis of intestinal lesions. An understanding of the function of these cells will require additional study.     

Cytologic, histologic, and immunohistochemical features of lingual liposarcoma in a dog

A 9-year-old female spayed mixed-breed dog was presented to the referring veterinarian with a history of decreased appetite and difficulty with prehension and swallowing because of a firm oval mass in the tongue. On cytologic evaluation of a fine-needle aspirate of the mass there were numerous round to polygonal cells organized individually or in loose clusters with rare branching capillaries. The cells had eosinophilic granular cytoplasm, round to oval nuclei, and occasionally indistinct borders. The cytologic diagnosis was granular cell tumor (GCT) of the tongue. Impression smears of a biopsy sample of the lingual mass contained similar eosinophilic granular cells with variable numbers of clear vacuoles in the background, numerous perivascular arrangements, and occasional lipoblasts, suggestive of liposarcoma. On histologic examination the tumor was composed of numerous lipocytes with rare foci of round eosinophilic granular cells without evidence of vacuolation; occasionally, atypical mitotic figures were seen. Immunohistochemically, the cells were uniformly negative for periodic acid-Schiff and did not express smooth muscle actin, desmin, or cytokeratin but were immunoreactive for vimentin and S100. A diagnosis of well-differentiated liposarcoma was made on the basis of morphologic and immunohistochemical results. Eosinophilic granular cells may be a component of well-differentiated liposarcoma and are not limited to GCT. Liposarcoma should be considered in the differential diagnoses of lingual tumors in the dog when cytological evaluation reveals eosinophilic granular cells consistent with GCT.