Canine Oral Osteocartilaginous Malignant Amelanotic Melanoma with Pulmonary Metastasis

Background: Melanomas are typically malignant neoplasms commonly observed in the oral cavity of dogs. The classical presentation of melanomas with characteristic melanin pigmentation is easy to diagnose; however, in some cases, the lack of melanin production in the amelanotic oral tumors cause a delay in establishing the precocious diagnosis and consequent treatment. The aim of this report was to evaluate the histopathological and immunohistochemical aspects of an oral amelanotic melanoma with osteocartilaginous formation and metastasis in a dog, in a temporal way.Case: A 10-year-old male German Shepherd dog, presenting mouth bleeding with an amelanotic melanoma located between the upper incisors was received at the Veterinary Hospital of the Catholic University Dom Bosco (UCDB), Campo Grande, MS, Brazil. The animal was clinically evaluated and radiography was performed. The tumor was surgically removed and a sample was collected for histopathological examination that revealed spindloid and some epithelioid morphological cell types surrounded by a fibromatous matrix with moderate amounts of fibrovascular stroma. Approximately 1 month after surgical removal, recovery of the tumor was observed, and a second clinical analysis and collection of sample were performed. These procedures were repeated three times showing the same histopathological characteristics added by myxoid, chondroid, fibromatous tissue, and small groups of chondrocytes as well as central areas of irregular mineralized spicules. X-ray examination revealed proliferative and lytic bone infiltration in the jaw. Immunohistochemical analysis for melanocytic differentiation markers was performed showing positivity to Melan-A, tyrosinase and HMB-45 immunoreactivity, while no S100 reactivity was detected. After 11 months of the first biopsy, pleural effusion and radiopaque disseminated nodules of 1cm in the lungs were detected by X-ray. The animal died and necropsy was conducted. Multiple masses were observed in the lung and at the parietal pleura, suggesting lung metastasis by the positivity for Melan-A.Discussion: The dog was first diagnosed with fibromatous epulis based on the observation of fibroblastic tissue and spindle cells with intense vascularization associated to the site of the tumor and its macroscopic aspect. In the subsequent follow-ups the tumor displayed malignant characteristics observed by recurrence after each surgery, as the tumor returned even larger, aggressive, and infiltrative. From the second biopsy, the histopathological analysis showed the undifferentiated character of epithelioid neoplastic cells, demonstrated by the increase of cartilage and osteoid tissue and the mineral deposit. The phenomenon of the tumor stroma to form cartilage and bone is highlighted here because myxoid change and cartilage formation were frequently observed at the site where amelanotic spindle cells were actively proliferating. It is possible that neoplastic melanocytic cells themselves were involved in the development of the osteocartilaginous areas. Although no cytoplasmic melanin pigmentation was found in the tumor fragments, specific melanocytic markers for melanoma detected neoplastic melanocytes and unmelanized melanosomes. The positive reaction for Melan-A, HMB-45, and tyrosinase in the epithelioid, spindle, and cartilaginous cell groups of the neoplasia indicated amelanotic melanoma with osteocartilaginous differentiation. The negative HMB-45, S100, and tyrosinase expression in lung metastasis may be due to the fact that melanomas express aberrant markers and are also known to display occasional loss of their classic immunophenotype. Amelanotic melanoma can be underdiagnosed due to rapid progression of the tumor allied to the dedifferentiation ability of melanocytes. Thus, the follow up study of cell morphology and immunohistochemical analysis for melanogenic factors can be important determinants in diagnosis

Molecular detection of hemotrophic mycoplasmas among domiciled and free-roaming cats in Campo Grande, state of Mato Grosso do Sul, Brazil

Hemoplasmas are bacteria living in feline red blood cells. Feline hemoplasmosis is frequently associated with old male cats that have access to the streets. This study aimed to detect the presence of hemoplasma speciess in domiciled and free-roaming cats in Campo Grande, state of Mato Grosso do Sul (MS), Brazil, using molecular techniques. Between January 2013 and April 2013, EDTA-whole blood samples were collected from 151 domestic cats (65 free-roaming and 86 domiciled cats). Samples were subjected to PCR assays targeting hemoplasmas 16S rRNA, followed by sequencing, BLAST analysis and phylogenetic analysis. Results show an occurrence of 36.4% for hemoplasmas. Twenty-three cats (15.2%) were positive for 'Candidatus Mycoplasma haemominutum', 17 (11.2%) for M. haemofelis and 15 (9.9%) for 'Candidatus M. turicensis', from PCR. Coinfection by two or three hemoplasmas was found in 25 cats (16.6%). No statistically significant difference between genders or between lifestyles was observed for the presence of hemoplasmas among the cats. Results show different hemoplasma species are present in cat population (Campo Grande, MS, Brazil). It is suggested that a differential diagnosis for feline hemoplasmosis should be made when cats show nonspecific clinical signs of disease with systemic manifestation.Hemoplasmas são bactérias encontradas aderidas aos eritrócitos de felinos. A hemoplasmose felina está frequentemente associada a gatos velhos machos, sem raça definida e com acesso à rua. O presente estudo objetivou realizar a detecção molecular de espécies de hemoplasmas em gatos domiciliados e errantes em Campo Grande, estado do Mato Grosso do Sul (MS), Brasil. Entre janeiro/2013 e abril/2013, amostras de sangue foram colhidas de 151 gatos domésticos (65 errantes e 86 domiciliados) e avaliadas por PCR frente à presença de sequências do gene do 16S rRNA de hemoplasmas, seguidas de sequenciamento, análise pelo BLAST e análise filogenética. Os resultados deste estudo mostraram uma ocorrência de 36,4%. Vinte e três (15,2%) gatos mostraram-se positivos na PCR para ‘Candidatus Mycoplasma haemominutum’, 17 (11,2%) para Mycoplasma haemofelis, e 15 (9,9%) para ‘Candidatus Mycoplasma turicensis’. A co-infecção por dois ou três hemoplasmas ocorreu em 25 gatos (16,6%). Não foi observada diferença estatística significativa entre sexo e estilo de vida dos gatos amostrados e a presença de hemoplasmas. O estudo mostrou que diferentes espécies de hemoplasmas circulam na população de gatos (domiciliados e errantes) na cidade de Campo Grande, MS, Brasil. Sugere-se o diagnóstico diferencial para hemoplasmose felina em gatos que apresentam sinais clínicos inespecíficos de doença com manifestação sistêmica.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Molecular detection of hemotrophic mycoplasmas among domiciled and free-roaming cats in Campo Grande, state of Mato Grosso do Sul, Brazil

Hemoplasmas are bacteria living in feline red blood cells. Feline hemoplasmosis is frequently associated with old male cats that have access to the streets. This study aimed to detect the presence of hemoplasma speciess in domiciled and free-roaming cats in Campo Grande, state of Mato Grosso do Sul (MS), Brazil, using molecular techniques. Between January 2013 and April 2013, EDTA-whole blood samples were collected from 151 domestic cats (65 free-roaming and 86 domiciled cats). Samples were subjected to PCR assays targeting hemoplasmas 16S rRNA, followed by sequencing, BLAST analysis and phylogenetic analysis. Results show an occurrence of 36.4% for hemoplasmas. Twenty-three cats (15.2%) were positive for ‘Candidatus Mycoplasma haemominutum’, 17 (11.2%) for M. haemofelis and 15 (9.9%) for ‘Candidatus M. turicensis’, from PCR. Coinfection by two or three hemoplasmas was found in 25 cats (16.6%). No statistically significant difference between genders or between lifestyles was observed for the presence of hemoplasmas among the cats. Results show different hemoplasma species are present in cat population (Campo Grande, MS, Brazil). It is suggested that a differential diagnosis for feline hemoplasmosis should be made when cats show nonspecific clinical signs of disease with systemic manifestation

Maintenance of Trypanosoma cruzi, T. evansi and Leishmania spp. by domestic dogs and wild mammals in a rural settlement in Brazil-Bolivian border

Domestic dogs are considered reservoirs hosts for several vector-borne parasites. This study aimed to evaluate the role of domestic dogs as hosts for Trypanosoma cruzi, Trypanosoma evansi and Leishmania spp. in single and co-infections in the Urucum settlement, near the Brazil-Bolivian border. Additionally, we evaluated the involvement of wild mammals’ in the maintenance of these parasites in the study area. Blood samples of dogs (n = 62) and six species of wild mammals (n = 36) were collected in July and August of 2015. The infections were assessed using parasitological, serological and molecular tests. Clinical examination of dogs was performed and their feeding habits were noted. Overall, 87% (54/62) of sampled dogs were positive for at least one trypanosomatid species, in single (n = 9) and co-infections (n = 45). We found that 76% of dogs were positive for T. cruzi, four of them displayed high parasitemias demonstrated by hemoculture, including one strain types TcI, two TcIII and one TcIII/TcV. Around 73% (45/62) of dogs were positive to T. evansi, three with high parasitemias as seen by positive microhematocrit centrifuge technique. Of dogs sampled, 50% (31/62) were positive for Leishmania spp. by PCR or serology. We found a positive influence of (i) T. evansi on mucous pallor, (ii) co-infection by T. cruzi and Leishmania with onychogryphosis, and (iii) all parasites to skin lesions of sampled dogs. Finally, feeding on wild mammals had a positive influence in the Leishmania spp. infection in dogs. We found that 28% (5/18) coati Nasua nasua was co-infected for all three trypanosamatids, demonstrating that it might play a key role in maintenance of these parasites. Our results showed the importance of Urucum region as a hotspot for T. cruzi, T. evansi and Leishmania spp. and demonstrated that dogs can be considered as incidental hosts. Keywords: Canine, Neglected diseases, Pantanal, Sentinels hosts, Trypanosomatid