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A 7-year-old neutered female Doberman pinscher was presented with a palpebral nodule on the haired eyelid of the left eye. The nodule was removed surgically. Microscopically, the nodule was consistent with eyelid melanocytoma. The tumour was characterized by the presence of numerous lacunar and slit-like spaces filled by erythrocytes and interspersed throughout the neoplastic melanocytes. Immunohistochemically, these spaces were lined by cells expressing PNL2, but the cells were negative for factor VIII and CD31. [corrected] These findings were consistent with neoplastic melanocytes without endothelial cell participation. This feature was interpreted as 'vasculogenic mimicry', a mechanism of tumour angiogenesis that is well-recognized in human melanomas, but has not yet been reported in melanomas in animals.

In dogs, inflammatory mammary carcinoma is a clinicopathological entity characterized by rapid progression and aggressive behavior from onset of disease. Reported median survival time is short, with no effective treatment options. The aims of this prospective, noncontrolled clinical trial were to investigate outcome variables and safety profile of toceranib, thalidomide and piroxicam with or without hypofractionated radiation therapy in dogs with measurable histologically confirmed inflammatory mammary carcinoma that underwent a complete staging. Eighteen dogs were enrolled: 14 received medical treatment, and 4 were treated with hypofractionated radiation therapy and medical therapy. Overall, median time to progression was 34 days and median survival time was 109 days. In dogs treated with medical therapy, overall response rate was 21%, and clinical benefit rate (CBR) was 64%; median time to progression was 28 days and median survival time was 59 days. In dogs receiving medical therapy and undergoing radiation therapy, overall response rate and clinical benefit rate were 100%, with significantly longer time to progression (156 days) and survival time (180 days). Overall, treatment was well tolerated, with mild gastrointestinal and dermatological adverse events. Although the optimal treatment to this disease remains uncertain, the current approach consisting of systemic anti-angiogenic drugs with or without hypofractionated radiation therapy, provided clinical benefit in a significant proportion of dogs and should, therefore, be further explored.

In humans, the aryl hydrocarbon receptor (AHR) gene battery constitutes a set of contaminant-responsive genes, which have been recently shown to be involved in the regulation of several patho-physiological conditions, including tumorigenesis. As the domestic dog represents a valuable animal model in comparative oncology, mRNA levels of cytochromes P450 1A1, 1A2 and 1B1 (CYP1A1, 1A2 and 1B1), AHR, AHR nuclear translocator (ARNT), AHR repressor (AHRR, whose partial sequence was here obtained) and cyclooxygenase-2 (COX2) were measured in dog control tissues (liver, skin, mammary gland and bone), in 47 mast cell tumors (MCTs), 32 mammary tumors (MTs), 5 osteosarcoma (OSA) and related surgical margins. Target genes were constitutively expressed in the dog, confirming the available human data. Furthermore, their pattern of expression in tumor biopsies was comparable to that already described in a variety of human cancers; in particular, both AHR and COX2 genes were up-regulated and positively correlated, while CYP1A1 and CYP1A2 mRNAs were generally poorly expressed. This work demonstrated for the first time that target mRNAs are expressed in neoplastic tissues of dogs, thereby increasing the knowledge about dog cancer biology and confirming this species as an useful animal model for comparative studies on human oncology.

International audience; The study of influenza type A (IA) infections in wild mammals populations is a critical gap in our knowledge of how IA viruses evolve in novel hosts that could be in close contact with avian reservoir species and other wild animals. The aim of this study was to evaluate the susceptibility to infection, the nasal shedding and the transmissibility of the H7N1 and H5N1 highly pathogenic avian influenza (HPAI) viruses in the bank vole (Myodes glareolus), a wild rodent common throughout Europe and Asia. Two out of 24 H5N1-infected voles displayed evident respiratory distress, while H7N1-infected voles remained asymptomatic. Viable virus was isolated from nasal washes collected from animals infected with both HPAI viruses, and extra-pulmonary infection was confirmed in both experimental groups. Histopathological lesions were evident in the respiratory tract of infected animals, although immunohistochemistry positivity was only detected in lungs and trachea of two H7N1-infected voles. Both HPAI viruses were transmitted by direct contact, and seroconversion was confirmed in 50% and 12.5% of the asymptomatic sentinels in the H7N1 and H5N1 groups, respectively. Interestingly, viable virus was isolated from lungs and nasal washes collected from contact sentinels of both groups. The present study demonstrated that two non-rodent adapted HPAI viruses caused asymptomatic infection in bank voles, which shed high amounts of the viruses and were able to infect contact voles. Further investigations are needed to determine whether bank voles could be involved as silent hosts in the transmission of HPAI viruses to other mammals and domestic poultry.

The expression of Ki67, BCL-2, and COX-2 was investigated in 53 canine cutaneous mast cell tumors (MCTs) by immunohistochemistry and quantitative real time polymerase chain reaction (qPCR) to evaluate their prognostic significance and the association with the histologic grading and the mitotic index (MI). MCTs were graded according to the Patnaik grading system and the novel 2-tier grading system proposed by Kiupel. The numbers of mitotic figures/10 high-power fields (MI) were counted. Both grading systems were significantly associated with prognosis. The Patnaik grading was of limited prognostic value for grade 2 MCTs, with 23% being associated with mortality. The concordance among pathologists was strongly improved by the application of the 2-tier grading system, and 71% of high-grade MCTs were associated with a high mortality rate. MI and Ki67 protein expression were significantly associated with grading and survival. No significant association between BCL-2 protein expression and either grading system or health status was observed. BCL-2 mRNA expression was significantly higher in grade 2 than in grade 1 MCTs, while no statistically significant differences were detected between low- and high-grade MCTs. The increased BCL-2 mRNA level was significantly associated with increased mortality rate. The COX-2 protein expression was detected in 78% of the MCTs investigated. However, neither association with the tumor grade nor with the health status was observed. COX-2 mRNA was significantly up-regulated in MCTs compared to surgical margins and control skin tissue, but it was neither associated with tumor grade nor with survival.

The histological status of the thymus, blood cortisol concentration and circulating neutrophil:lymphocyte ratio were evaluated in 349 slaughtered beef cattle, to assess the potential of these parameters as indirect biomarkers of the illegal use of corticosteroids in meat production. The livers of 20 of the animals were analysed chemically for residues of corticosteroids. The morphology of the thymus was examined for adipose tissue infiltration, cortical atrophy and ‘starry sky’ appearance, and on the basis of these characteristics, the animals were considered to be negative, suspected or positive for illegal corticosteroid treatment. The animals considered to be negative had a mean cortisol concentration that was significantly higher (29 ng/ml) than that of the animals suspected for corticosteroid treatment (22 ng/ml). Using the chemical analysis as the gold standard for identifying illegally treated animals, the histological examination of the thymus had a sensitivity of 100 per cent and a specificity of 85 per cent. The samples that were positive by chemical analysis had cortisol concentrations of less than 2·0 ng/ml, whereas the mean cortisol concentration of the negative samples was 10·3 ng/ml.

The ongoing H5N1 Asian epidemic is currently affecting a number of avian species including ducks. These birds are an important part of the poultry industry in the affected countries, and it is likely that they are acting as a reservoir of infection. Ten Pekin ducks were challenged with 100 μl containing 107 50% egg infective dose of the highly pathogenic avian influenza virus (HPAIV) A/Duck/Vietnam/12/05 (H5N1), administered by an intra-nasal and oral route. Clinical symptoms were recorded twice a day up to 14 days postinfection (dpi). Clinical signs were first noted at 2 dpi, with conjunctivitis and slight depression, and progressed over a period of 1–3 days to severe neurologic signs consisting of torticollis, incoordination, tremors, and seizures. Survival times varied from 3 to 7 dpi. On postmortem examination, hemorrhages were observed in the duodenum, ceca, proventriculus, ventriculus, trachea, pancreas, and brain. Histologic lesions, as well as immunohistochemistry positivity, were recorded in the pancreas and brain. In situ hybridization revealed viral antigen associated with acinar pancreatic cells, bronchial epithelial cells, and with cells of the central nervous system as well as neurons of the submucosal plexus of the duodenum. Our experimental findings agree with those previously observed in ducks naturally infected with HPAIV H5N1 viruses, confirming the acquired viral neurotropism and pancreatotropism, as previously noted in other avian species, as well as in humans.

SQUAMOUS cell carcinoma of the sinuses has been described in many animal species, particularly in horses (Junge and others 1984, Dixon and Head 1999, Head and Dixon 1999), dogs (Rogers and others 1996) and cats (Murphy and others 1989, Mukaratirwa and others 2001). However, none has been reported in captive, wild bovids kept in zoos. Among the order Artiodactyla, one cutaneous squamous cell carcinoma has been described in a Wyoming pronghorn (Antilocapra americana americana) (Effron and others 1977). The addax (Addax nasomaculatus), of the order Artiodactyla, class Bovidae, family Antilopinae, is the most desertadapted of the antelopes, living in sandy and stony regions of the Sahara desert (Kingdon 1997). This short communication describes the gross and microscopic examination of a captive addax living in a zoo, which had squamous cell carcinoma of the frontal sinus and nasal conchae, with pulmonary and lymph node metastases. A 10-year-old, 90 kg, male addax kept in the municipal zoo of Lignano, northern Italy, showed respiratory distress, a mucous bloody nasal discharge, anorexia and cachexia. Antibiotic therapy with intramuscular enrofloxacin failed to reduce the respiratory signs, and the addax was euthanased. A few months previously, a small cutaneous nodule in the frontal region of the animal’s head had been surgically excised. At postmortem examination, the nodule had regrown; an ovoid, 5 x 4 cm area of erosion on the right side of the frontal bone surface was evident. The bone was friable; its consistency was reduced and easy to cut. The frontal sinus contained a yellowish, spongy mass in its ventral portion, which also invaded the caudal nasal conchae through the ethmoidal bone. The same type of proliferative mass was found in the orbital cavity at the emergence of the optic nerve, and appeared to be connected to the frontal sinus. Haemorrhage was detected in the brain cortex and in the maxillary sinus. The retropharyngeal lymph nodes were hyperplastic, and some whitish nodules of approximately 0·5 cm in diameter were recognised in the lung. No other organs were involved. Samples of the neoplastic mass, retropharyngeal lymph nodes, the cutaneous nodule, lung, liver and kidney were fixed for routine histopathology. Histologically, the mass showed a diffuse proliferation of neoplastic cells of epithelial origin, with a high degree of pleomorphism and squamous differentiation (Fig 1). The tumour cells had large, ovoid and hyperchromatic nuclei, with prominent multiple nucleoli, and abundant eosinophilic cytoplasm. They showed variable degrees of squamous metaplasia and keratinisation, with an appearance of ‘horn pearl’ formation. The neoplastic growth was infiltrative, with large areas of necrosis and haemorrhage. The mitotic activity was high, at three to four mitotic figures per high-power field. The retropharyngeal lymph nodes, the nodule excised from the skin and the lung (Fig 2) were affected by neoplastic proliferation characterised by the same histological features as the mass found in the sinuses. In contrast, the liver and the kidney were not involved. Immunohistochemistry was performed on selected sections of neoplastic tissue using monoclonal mouse antihuman cytokeratin antibodies (M821, 1:100; Dako). Antigen retrieval was obtained by digestion with trypsin for 30 minutes at 37°C. The EnVision Peroxidase (K4000; Dako) detection system, using 3,3′-diaminobenzidine tetrahydrochloride (D-5905; Sigma) as the chromogen, was applied. The neoplastic tissue showed strong cytoplasmic positivity to cytokeratin, thus confirming the epithelial origin of the neoplasia. On the basis of the gross, microscopic and immunohistochemical characteristics, a diagnosis of squamous cell carcinoma of the frontal sinus and nasal conchae with retropharyngeal lymph node and pulmonary metastases was made. The many types of tissue in the nasal cavity give rise to a variety of types of neoplasm. Almost all of the malignant neoplasms reported are of epithelial origin, but some neoplasms of mesenchymal origin are also reported (Madewell and others 1976). Considering the influence of the gross anatomy of the nasal and paranasal sinus cavities on the growth pattern and spread of sinonasal tumours, neoplasias in this region can grow by expansion alone or by expansion and infiltration. Tumours of the frontoconchal sinus can readily extend via the large frontomaxillary ostium into the caudal maxillary sinus, and vice versa (Head and Dixon 1999). In the present case, the tumour invasion within the sinus cavities did not allow identification of the primary site of the tumour. However, the neoplastic growth pattern indicated that the tumour had expanded both cranially and caudally, following the anatomical communications between the sinuses. Furthermore, metastases in the retropharyngeal lymph nodes, lung and skin were detected. Distant metastases have seldom been recorded with sinonasal tumours, lymph node metastases being more commonly recorded (Head and Dixon 1999). The present case contributes to the limited information available on tumour pathology in captive wild Bovidae, highFIG 2: Multiple metastatic foci of neoplastic involvement are seen in the lung. Haematoxylin and eosin. Bar=25 μm FIG 1: Histological appearance of the neoplastic mass. There is a diffuse proliferation of neoplastic cells of epithelial origin, with high grade pleomorphism, mitotic activity and squamous differentiation. Large areas of necrosis are also present. Haematoxylin and eosin. Bar=100 μm

At the end of 2008, two young dogs, a threeyear- old male Maltese and a one-year-old male Lhasa apso, belonging to the same dog breeder (Veneto region, north-eastern Italy), died with clinical signs of renal failure. At postmortem examination, bilateral nephritis with green-yellowish uroliths was

TUMOURS are not uncommon in domestic and pet birds ([Petrak and Gilmore 1982][1], [Reece 2003][2]), but are an unusual finding in free-living and captive birds ([Effron and others 1977][3], [Siegfried 1983][4], [Dillberger and others 1987][5], [Renner and others 2001][6]). Most reports of neoplasia