Ganglioneuromatosis of the Gallbladder in a Dog with Cholecystitis and Cholestasis.

A 2-year-old entire female mixed-breed dog was presented with signs of cholestasis. Abdominal ultrasonography revealed a gallbladder with a thickened and hyperechoic wall and luminal calculi. Exploratory laparotomy with cholecystectomy was performed and histopathological examination of the specimens from the cholecystectomy demonstrated extensive proliferation of large, prominent nerves containing ganglion cells with no atypia mainly located in the gallbladder mucosa. The neural nature of these components was confirmed by immunohistochemical labelling with antibodies specific for synaptophysin, glial fibrillary acidic protein, S100 protein and neurofilaments. Based on these findings, the lesion was diagnosed as ganglioneuromatosis. Reports of ganglioneuromatosis in animals have so far been restricted to the intestine. This is the first case of ganglioneuromatosis affecting the gallbladder in an animal in which no intestinal involvement was apparent.

Immunohistochemical expression of MDR1-Pgp 170 in canine cutaneous and oral melanomas: pattern of expression and association with tumour location and phenotype.

Canine melanoma (CMM) more commonly affects the oral mucosa and the cutis. CMM shares several features with human melanomas (HMM), included resistance to a broad variety of antineoplastic chemotherapy agents. P-glycoprotein 1 (Pgp) expression is a well-recognized feature of multi-drug resistance and the purpose of this study was to investigate its expression in treatment naïve CMM. We also investigated Pgp association with tumour location and histological features. Histology records of CMM were retrieved, including patients from 2012-2014. Twenty-five cases of CMM were included in this study. Results revealed that Pgp is expressed in CMM and oral tumours were more likely to have a membranous Pgp expression (100%) than cutaneous tumours (66.6%) (P = 0.010). Cytoplasmic and nuclear Pgp expression could also be identified. Results of this study bring useful data that help in understanding one of the possible mechanisms responsible of intrinsic chemotherapy resistance in canine CMM.

Cutaneous Heterotopic Brain Tissue (Neuroglial Choristoma) with Dysplastic Features in a Kitten.

A 3-month-old, male European shorthair kitten exhibited an ill-defined, soft mass on the skin of the frontal head, which was present since birth. The surgically resected tissue was representative of a discrete dermal and subcutaneous mass comprising islands of neurons, glial and meningothelial elements, sometimes atypical or dysplastic, separated by dense collagenous connective tissue. There was no evident connection between this tissue and the brain. Immunohistochemical examination confirmed the presence of neurons and a pleocellular glial population, supporting a diagnosis of cutaneous neuroglial choristoma believed to be secondary to sequestered (resolved) meningoencephalocoele. Ectopic brain tissue is very rare in small animals. Some atypical features displayed by this tissue may be misdiagnosed as neoplasia. Communication between surgeon and pathologist to clarify the relationship of the lesion to surrounding structures is helpful to avoid misdiagnosis.

Cartilaginous Tumors of the Larynx and Trachea in the Dog: Literature Review and 10 Additional Cases (1995-2014).

Cartilaginous tumors of the larynx and trachea are uncommon in the dog. The authors describe 10 cases diagnosed between 1995 and 2014 and review 16 cases in the literature. Seven of our cases were tracheal and 3 were laryngeal. Two of the laryngeal tumors were chondromas, which have not been previously reported in this site. The third laryngeal tumor was a myxochondroma. Of the 7 tracheal tumors, 6 arose from the ventral tracheal wall, including 2 that were extraluminal. Tracheal tumor types included chondrosarcoma (n = 3), chondroma (n = 2), and osteochondroma (n = 2). All of the laryngeal tumors and 5 of 7 of the tracheal tumors occurred in adult dogs (aged 5-11 years). The 2 tracheal osteochondromas were in young dogs (3-4 months) and were intrathoracic, while the remaining tracheal tumors were cervical. Surgical excision had a good outcome in most cases. Combining our 10 cases with the 16 previously reported cases showed that 6 (27%) of the affected dogs were Arctic breeds (Alaskan Malamute or Siberian Husky) suggesting a predisposition in this type of dog.

N-cadherin expression in feline mammary tumors is associated with a reduced E-cadherin expression and the presence of regional metastasis.

The cadherin family of adhesion molecules regulates cell-cell interactions. N-cadherin is expressed by neural and fibroblast cells but not by normal epithelial cells. In human medicine, the role of N-cadherin in breast cancer remains controversial, but some studies have described the switch from E-cadherin to N-cadherin as a critical step in the malignant progression of neoplastic cells. The present study was carried out on 160 feline mammary tumors (21 adenomas and 139 carcinomas). The relationship between the immunohistochemical expression of N-cadherin in neoplastic epithelial cells and 2 established prognostic factors such as regional metastasis and tumor grade was examined. The results of the study showed a statistically significant relation between the expression of N-cadherin and the 2 prognostic factors, and also a reduced expression of E-cadherin in tumors that expressed N-cadherin.

Naturally acquired visceral leishmaniosis in a captive Bennett's wallaby (Macropus rufogriseus rufogriseus).

A high prevalence of leishmaniosis has been reported from an increasing number of domestic and wild mammals around the world. In Australian macropods, Leishmania spp infection has been occasionally described in its cutaneous form only. The purpose of this report is to present a case of fatal visceral leishmaniosis in a captive Bennett's wallaby in Madrid, Spain, which was investigated by detailed macroscopic, histologic, and immunohistochemical examinations.

Intrapancreatic ectopic splenic tissue in dogs and cats.

Ectopic splenic tissue in the pancreas is a rare incidental finding in man that is often mistaken for pancreatic neoplasia. This condition is documented rarely in animals. This report describes the clinical and pathological features of four cases of intrapancreatic accessory spleens in dogs and cats. This is the first description of this lesion in the dog. The lesions comprised firm, well-demarcated, dark red, spherical masses that were composed microscopically of normal splenic tissue. The possible origin, differential diagnoses and potential practical significance of these lesions are discussed.

Reduced expression of E-cadherin and ß-catenin and high expression of basal cytokeratins in feline mammary carcinomas with regional metastasis.

Feline mammary carcinomas are highly aggressive neoplasms. Several mechanisms are thought to be involved in their progression, including the loss of epithelial adhesion molecules. The present study was carried out on 21 adenomas and 139 mammary carcinomas. Of the carcinomas, 66 were not reported to have metastasized, while the remaining 73 had evidence of regional lymph node metastasis at the moment of diagnosis. The relationship was examined between the expression of the E-cadherin-ß-catenin complex and basal (CK5/6, CK14) and luminal (CK8/18) cytokeratin expression. In the medical literature, carcinomas expressing basal cytokeratins are reported as having a poor prognosis in human breast cancer. Results revealed that preservation of the expression of E-cadherin and ß-catenin is a significant feature of carcinomas without metastasis, whereas carcinomas with metastasis reveal the loss of one or both adhesion molecules. Additionally, basal cytokeratin expression was statistically associated with the presence of regional metastasis. Furthermore, the expression of E-cadherin-ß-catenin was significantly correlated with the high expression of CK18 and low expression of CK5/6.

Intraepidermal glandular carcinoma of the nipple (mammary Paget-like disease) in 2 dogs.

Mammary Paget disease, characterized by diffuse infiltration of the nipple and areolar epidermis by carcinoma cells, develops in 1% to 3% of human mammary carcinomas. The purpose of this article is to present 2 cases of intraepidermal adenocarcinoma that resembled human mammary Paget disease, histologically and immunohistochemically, in dogs with underlying mammary carcinoma.

Gammopathy in a Spanish dog infected with Bartonella henselae.

Generalised pyogranulomatous disease and hyperviscosity syndrome associated with a presumed monoclonal gammopathy was diagnosed in a three-year-old intact female Pomeranian. The Bartonella henselae antibody titer was 1:64 and Bartonella species DNA was amplified from the splenic tissue. Monoclonal gammopathies in dogs are typically associated with plasma cell and lymphoid dyscrasias and other inflammatory or infectious diseases such as ehrlichiosis and leishmaniosis. Based on this case report, infection with Bartonella species should also be added to the differential diagnoses for gammopathy in dogs. To the authors' knowledge, this is the first report of molecular evidence of Bartonella species infection in a sick dog in Spain.

Cyclooxygenase-2 expression is related with localization, proliferation, and overall survival in canine melanocytic neoplasms.

A direct relationship has been firmly established between cyclooxygenase-2 (COX-2) expression and malignant behavior in human melanoma. This report examines the relationship between COX-2 expression and tumor location, mitotic and proliferative indices, degree of T CD3(+) lymphocyte infiltration, overall survival, and frequency of recurrence and metastasis of 57 melanocytic tumors (25 oral and 32 cutaneous). COX-2 was highly or moderately expressed in 88% of oral neoplasms (22 of 25), whereas for their cutaneous counterparts, COX-2 expression was low or insignificant in 75% of cases (24 of 32). High and moderate COX-2 expression levels were observed in 73% of melanocytic tumors with a mitotic index ≥ 3 per 10 high-power fields (26 of 36), whereas in 81% of tumors with a mitotic index < 3 (17 of 21), expression was mild or absent. There were 41 cases with known clinical outcomes; of those showing high, moderate, and mild COX-2 expression, 83.3% (10 of 12), 37.5% (3 of 8), and 25% (2 of 8) died, respectively, whereas 100% of animals showing no COX-2 expression (13 of 13) were still alive at the last follow-up. COX-2 expression was statistically correlated with tumor location, mitotic and percentage Ki-67 proliferative indices, and overall survival, frequency of neoplastic recurrence and metastasis. Regression analysis also showed disease-specific predictive value for COX-2 expression for subjects with melanocytic neoplasms. Additionally, only high COX-2 expression showed significant differences in overall survival, in comparison with moderate, mild, or absent expression. These results suggest that high COX-2 expression may be considered a prognostic biomarker and potentially as a target for therapeutic and preventive strategies in canine melanocytic neoplasms.

Histopathological lesions in 15 cats with leishmaniosis.

Recent research into the prevalence of Leishmania infantum infection in the Mediterranean basin points to the involvement of cats as a reservoir host, but only sporadic cases of feline leishmaniosis have been reported. Feline leishmaniosis presents primarily as cutaneous disease and diagnosis is based on the demonstration of the parasite by skin biopsy. The present report describes the microscopical changes in tissue biopsies from 15 cats with leishmaniosis. The biopsies were derived from the skin, ocular tissue and mucocutaneous junctions. The most common histopathological feature was diffuse granulomatous inflammation with macrophages containing numerous amastigotes. Other patterns included granulomatous perifolliculitis and lichenoid interface dermatitis, where there were fewer parasitized macrophages. The presence of amastigotes was confirmed by immunohistochemistry in each case. The results of the study confirm the value of histopathological and immunohistochemical techniques for the diagnosis of feline leishmaniosis.

Chondro-osteoblastic metaplasia in canine benign cutaneous lipomas.

Lipomas are common benign adipose tissue tumours in dogs. Variants of lipomas are characterized by an additional component (e.g. capillaries in angiolipomas or fibrous connective tissue in fibrolipomas). In human medicine, the presence of cartilage or bone within a lipoma is a rare event. Mechanical stress, tropic disturbances, contact with periosteum and other unknown factors may contribute to this transformation. The present report describes the clinical, gross and microscopical findings of four cases of chondrolipoma and two cases of osteolipoma in the canine skin. The possible histogenesis for these tumours in the dog is discussed.

Immunohistochemical characterization and evaluation of prognostic factors in canine oral melanomas with osteocartilaginous differentiation.

Melanomas are the most common malignant oral neoplasm in dogs. Osteocartilaginous differentiation in oral melanomas is a rare feature described both in veterinary and human medicine. Here, 10 cases of this type of neoplasm were used to study their immunohistochemical, biological, and clinical characteristics. Reactivity for S100 and melan A antigen was evaluated, and 4 prognosis factors (mitotic index, invasiveness of epithelium, nuclear atypia, and proliferation index) were analyzed and correlated with the clinical course of the neoplasms after diagnosis. Immunohistochemical analysis of the studied neoplasms, including the osteocartilaginous areas, showed positive immunoreaction for S100 and melan A, except in one dog, which was negative for melan A. Analysis of the results showed that oral melamonas with osteocartilaginous differentiation have a clinical course similar to that of other melanomas in the oral cavity. Analysis of the mitotic index and the expression of proliferation marker Ki-67 could be useful tools for predicting the biological behavior of these neoplasms.

Canine carcinosarcomas in the head.

Four cases of neoplasms in the heads of old dogs were studied. All the dogs showed both carcinomatous and sarcomatous malignant components in an admixed growing pattern. Histologic analysis of the tumors showed that the carcinomatous cells resembled squamous cell carcinoma in all dogs except one, where an adenoid arrangement of the neoplastic cells was also observed. The sarcomatous component showed osteoid matrix produced by pleomorphic poorly differentiated cells, which is regarded as a typical feature of osteosarcomas. Immunohistochemical analysis demonstrated that the components were positive only for cytokeratin (carcinomatous component) or vimentin (sarcomatous component). This observation led us to classify the neoplasms as true carcinosarcomas, thus providing evidence of a new preferential location for this unusual tumor in dog.

Acute paraplegia associated with vasculitis in a dog with leishmaniasis.

A 14-month-old female crossbreed dog with leishmaniasis, receiving allopurinol, was presented with acute paraplegia. A diagnosis of renal failure with pelvic limb lower motor neuron signs was made and the dog was euthanased. Histopathological examination demonstrated leukocytoclastic vasculitis in multiple organs. Malacia and haemorrhage affecting the spinal cord was associated with multiple foci of vasculitis within the nervous tissue. Rupture and thrombosis of inflamed vessels caused haemorrhage in the spinal cord and subsequent paralysis.

Primary central nervous system T-cell lymphoma in a cat.

A 5-year-old intact male Persian cat was presented with progressive neurologic deficits, hyperesthesia, hyperreflexia, ataxia, and intention tremors, which resulted in death. Serologic tests for feline leukemia virus and feline immunodeficiency virus infection were negative. Neurohistologic examination revealed the presence of pleomorphic cellular infiltrates in cerebral leptomeninges and around parenchymal vessels. The majority of infiltrating cells were uniformly immunostained using an antiserum directed against T cells. Immunohistochemical examination of paraffin-embedded brain sections for the antigens of canine distemper virus, herpesvirus, Borna virus, and Toxoplasma gondii were negative. Histologic and immunohistochemical studies revealed a primary central nervous system T-cell lymphoma affecting the brain.

Turkey rhinotracheitis virus and Escherichia coli experimental infection in chickens: histopathological, immunocytochemical and microbiological study.

The aim of this study was to evaluate the response of chickens to a combined infection with turkey rhinotracheitis virus (TRTV) and Escherichia coli O78:K80. Groups of specific-pathogen-free chickens were inoculated by eyedrop and intranasal routes with TRTV and/or E. coli O78:K80. Presence of E. coli O78:K80, histopathological changes and tissue distribution of viral antigen in the respiratory tract of chickens were evaluated. Dual infection resulted in increased severity of clinical signs, and macroscopic and microscopic lesions compared with those groups given single infections. All 36 chickens inoculated with TRTV plus E. coli O78:K80 showed severe rhinitis. Moreover, periorbital edema and fibrinous airsacculitis and pericarditis were observed in one of the three chickens inoculated with both agents and sacrificed at day 5 p.i. In addition, purulent material in the air spaces of the cranial bones was seen in three of the six animals from the same group sacrificed at days 5 and 7 p.i. The distribution of viral antigen in tissues was similar in groups inoculated with TRTV and TRTV plus E. coli, but viral antigen was detected only in main bronchi of chickens from the latter group. The quantity of E. coli O78:K80 isolated from the nasal cavity was greater in the group given dual infection. The results obtained suggest that TRTV may act as primary agent, enhancing E. coli multiplication. The lesions observed in the group inoculated with both agents could correspond to an initial stage of swollen head syndrome (SHS) and contribute to the hypothesis that SHS could be due to a mixed infection with TRTV and E. coli.

Epidermal immunocompetence in canine leishmaniasis.

The antigen-presenting cell function of the epidermis was investigated immunocytochemically in 16 dogs with different types of skin lesions induced by Leishmania infection. The degree of epidermal immunocompetence was evaluated according to the presence of Langerhans cells (LC) and keratinocytes expressing class II major histocompatibility complex (MHC II) molecules on the one hand, and the relative numbers of macrophages, T cells, and parasites in the dermis on the other, as described for human cutaneous leishmaniasis. In alopecic dermatitis, appropriate numbers of LC and MHC II-positive keratinocytes were shown to be associated with a mild T cell infiltration without significant numbers of parasites. By contrast, when the epidermis lacked antigen-presenting cells, as occurred in nodular lesions, macrophages and parasites massively infiltrated the dermis. Ulcerative lesions showed intermediate patterns of inflammation. These results suggest that dogs with alopecic dermatitis develop an effective control of the infection, whereas those with a generalized nodular disease mount an impaired immune response against the parasite. Skin lesions in dogs infected by Leishmania might not only have a prognostic value, but also represent a suitable model to study the natural course of human cutaneous leishmaniasis.