RESUMO
Relata-se um caso de melanoma oral disseminado em uma cadela de dois anos, com protrusão de bulbo ocular unilateral e quadro convulsivo progressivo. Os exames de imagem revelaram aumento de volume nas regiões submandibular, maxilar e cerebral, padrão nodular pulmonar e aumento das dimensões ovarianas. A citologia da massa submandibular indicou proliferação epitelial maligna, enquanto a biópsia excisional foi sugestiva de melanoma amelanótico. Na necropsia, havia uma massa gengival localmente infiltrativa e nodulações brancas nos linfonodos, nos rins, no pulmão, no cérebro e nos ovários, indicativas de metástase. O diagnóstico histopatológico consistiu de neoplasia maligna metastática indiferenciada, indicativo de melanoma amelanótico. Células caracterizadas por núcleo com cromatina espessa, múltiplos nucléolos bem evidentes, mitoses atípicas e multinucleações consistiram nos principais critérios de malignidade. No espaço peritrabecular ósseo facial, havia rara diferenciação pigmentar melanocítica, confirmada histoquimicamente pela técnica de Fontana-Massom e Giemsa. Algumas células foram positivas pela imuno-histoquímica para PNL-2 e Melan-A, e o diagnóstico de melanoma amelanótico disseminado foi firmado. A indiferenciação neoplásica marcante, com disseminação metastática multissistêmica e acometimento mútuo de sítios anatômicos pouco comuns, conjuntamente com a ampla variação dos padrões celulares, foi responsável pelo desafio diagnóstico do presente caso, ressaltando o papel decisivo da imuno-histoquímica para confirmação diagnóstica. A importância clínica deste trabalho consiste ainda em alertar a comunidade clínica e científica acerca da dificuldade diagnóstica, devendo-se considerar o melanoma amelanótico como diferencial mesmo em casos de lesões orais menos perceptíveis e/ou desprovidas de pigmentação.(AU)
A case of disseminated oral melanoma in a two year old female dog with unilateral protuberance of the eye bulb and progressive seizure is described. Imaging exams revealed increase of the submandibular, maxillary and cerebral regions, nodular pattern in lungs and increased ovarian dimensions. The cytology of the submandibular mass indicated a malignant epithelial proliferation, whereas the excisional biopsy indicated an amelanotic melanoma. At necropsy, a locally infiltrating gingival mass and white nodules in the lymph nodes, kidneys, lung, brain and ovaries were observed, indicative of metastases. Histopathological diagnosis consisted of an undifferentiated malignant metastatic neoplasm. Nucleus with coarse chromatin, prominent nucleoli, bizarre mitotic figures and multinucleated cells were the major malignant features. There was a poor melanocytic pigment differentiation in the peritrabecular space of facial bones, confirmed by Fontana-Masson and Giemsa histochemical techniques. Only a few cells were immunohistochemically positive for PNL-2 and Melan-A and the diagnosis of a disseminated amelanotic melanoma was performed. The diagnostic challenge was based on marked neoplastic undifferentiation, with multisystemic metastasis and mutual involvement of uncommon anatomic sites, associated with a large variability of cellular patterns, highlighting the decisive role of immunohistochemistry for diagnostic confirmation. Therefore, the clinical importance of this study is to warn the clinical and scientific community about the diagnostic challenge, considering the amelanotic melanoma as a differential even in cases of poorly apparent and/or nonpigmented oral lesions.(AU)
Assuntos
Animais , Feminino , Cães , Neoplasias Bucais/veterinária , Melanoma Amelanótico/complicações , Melanoma Amelanótico/veterinária , Neoplasias Ovarianas/veterinária , Metástase NeoplásicaRESUMO
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.[...](AU)
Assuntos
Animais , Masculino , Adulto , Cães , Melanoma Amelanótico/veterinária , Neoplasias Bucais/veterinária , Metástase Neoplásica/diagnóstico por imagem , Pulmão/patologia , Imuno-Histoquímica/métodosRESUMO
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.[...]
Assuntos
Masculino , Animais , Adulto , Cães , Melanoma Amelanótico/veterinária , Metástase Neoplásica/diagnóstico por imagem , Neoplasias Bucais/veterinária , Imuno-Histoquímica/métodos , Pulmão/patologiaRESUMO
Melanomas are the most common oral malignancy in dogs. Cell proliferation and connexin expression has been shown to differ in canine melanotic and amelanotic oral melanomas. This study aimed to analyze the c-Kit protein expression in melanotic and amelanotic melanomas from canine buccal cavity. A total of 34 canine buccal melanomas (19 melanotic and 15 amelanotic).were collected. The amelanotic melanomas presented faster evolution and higher incidence of metastasis than melanotic tumors. A significantly higher number of c-Kit positive cells were observed in amelanotic neoplasms. In addition, the intensity of c-Kit immunolabeling was predominantly stronger in amelanotic melanomas. These results confirm a potential role for c-Kit in canine oral melanomas with clear differences in expression patterns between the two histological types of tumor, melanotic and amelanotic. This study highlights the importance of a detailed study of c-Kit mutations in canine oral melanomas to better understand the molecular mechanisms implicated in the development of this disease...
Melanomas são as mais frequentes neoplasias malignas da cavidade bucal de cães. Sabe-se que a proliferação de células e expressão de conexina diferem em melanomas melanóticos e amelanóticos da cavidade bucal de cães. Este estudo analisou a expressão da proteína c-Kit em melanomas melanóticos e amelanóticos da cavidade bucal canina. Um total de 34 melanomas bucais caninos (19 melanóticos e 15 amelanóticos) foram coletados. Os melanomas amelanóticos apresentaram evolução mais rápida e maior incidência de metástase. Foi constatado um número significativamente maior de células positivas para c-Kit em neoplasias amelanóticas. Além disso, a intensidade de imunomarcação de c-Kit foi predominantemente mais forte em melanomas amelanóticos. Estes resultados confirmam um papel potencial para c-Kit em melanomas orais caninos, com diferenças claras em padrões de expressão entre os dois tipos histológicos de tumor, melanóticos e amelanóticos. Este trabalho destaca a importância de um estudo detalhado das mutações c-Kit em melanomas orais caninos para ser possível a melhor compreensão dos mecanismos moleculares envolvidos no desenvolvimento da doença...
Assuntos
Animais , Cães , Boca/patologia , Melanoma Amelanótico/veterinária , Melanoma/veterinária , Proteínas Proto-Oncogênicas c-kit/imunologia , Carga Tumoral , Imuno-Histoquímica/veterinária , Metástase Neoplásica/imunologia , Neoplasias Bucais/veterináriaRESUMO
Melanomas are the most common oral malignancy in dogs. Cell proliferation and connexin expression has been shown to differ in canine melanotic and amelanotic oral melanomas. This study aimed to analyze the c-Kit protein expression in melanotic and amelanotic melanomas from canine buccal cavity. A total of 34 canine buccal melanomas (19 melanotic and 15 amelanotic).were collected. The amelanotic melanomas presented faster evolution and higher incidence of metastasis than melanotic tumors. A significantly higher number of c-Kit positive cells were observed in amelanotic neoplasms. In addition, the intensity of c-Kit immunolabeling was predominantly stronger in amelanotic melanomas. These results confirm a potential role for c-Kit in canine oral melanomas with clear differences in expression patterns between the two histological types of tumor, melanotic and amelanotic. This study highlights the importance of a detailed study of c-Kit mutations in canine oral melanomas to better understand the molecular mechanisms implicated in the development of this disease(AU)
Melanomas são as mais frequentes neoplasias malignas da cavidade bucal de cães. Sabe-se que a proliferação de células e expressão de conexina diferem em melanomas melanóticos e amelanóticos da cavidade bucal de cães. Este estudo analisou a expressão da proteína c-Kit em melanomas melanóticos e amelanóticos da cavidade bucal canina. Um total de 34 melanomas bucais caninos (19 melanóticos e 15 amelanóticos) foram coletados. Os melanomas amelanóticos apresentaram evolução mais rápida e maior incidência de metástase. Foi constatado um número significativamente maior de células positivas para c-Kit em neoplasias amelanóticas. Além disso, a intensidade de imunomarcação de c-Kit foi predominantemente mais forte em melanomas amelanóticos. Estes resultados confirmam um papel potencial para c-Kit em melanomas orais caninos, com diferenças claras em padrões de expressão entre os dois tipos histológicos de tumor, melanóticos e amelanóticos. Este trabalho destaca a importância de um estudo detalhado das mutações c-Kit em melanomas orais caninos para ser possível a melhor compreensão dos mecanismos moleculares envolvidos no desenvolvimento da doença(AU)
Assuntos
Animais , Cães , Melanoma Amelanótico/veterinária , Melanoma/veterinária , Boca/patologia , Proteínas Proto-Oncogênicas c-kit/imunologia , Imuno-Histoquímica/veterinária , Neoplasias Bucais/veterinária , Carga Tumoral , Metástase Neoplásica/imunologiaRESUMO
Melanoma is a malignant neoplasm occurring in several animal species, and is the most frequently found tumor in the oral cavity in dogs. Melanomas are classified into two types: melanotic and amelanotic. Prior research suggests that human amelanotic melanomas are more aggressive than their melanotic counterparts. This study evaluates the behavior of canine melanotic and amelanotic oral cavity melanomas and quantifies cell proliferation and the expression of connexins. Twenty-five melanomas (16 melanotic and 9 amelanotic) were collected from dogs during clinical procedures at the Veterinary Hospital of the School of Veterinary Medicine and Animal Science of the University of São Paulo, Brazil. After diagnosis, dogs were followed until death or euthanasia. Histopathology confirmed the gross melanotic or amelanotic characteristics and tumors were classified according to the WHO. HMB45 or Melan A immunostainings were performed to confirm the diagnosis of amelanotic melanomas. Cell proliferation was quantified both by counting mitotic figures and PCNA positive nuclei. Expressions of connexins 26 and 43 were evaluated by immunohistochemistry, qRT-PCR and Western blot. Dogs bearing amelanotic melanomas presented a shorter lifespan in comparison to those with melanotic melanomas. Cell proliferation was significantly higher in amelanotic melanomas. Expressions of Connexins 26 and 43 were significantly reduced in amelanotic melanomas. The results presented here suggest that oral cavity melanotic and amelanotic melanomas differ regarding their behavior, cell proliferation and connexin expression in dogs, indicating a higher aggressiveness of amelanotic variants.
Assuntos
Doenças do Cão/patologia , Regulação Neoplásica da Expressão Gênica , Melanoma Amelanótico/veterinária , Melanoma/veterinária , Neoplasias Bucais/veterinária , Animais , Proliferação de Células , Conexina 26 , Conexina 43/genética , Conexinas/genética , Doenças do Cão/mortalidade , Doenças do Cão/fisiopatologia , Cães , Feminino , Masculino , Melanoma/mortalidade , Melanoma/patologia , Melanoma/fisiopatologia , Melanoma Amelanótico/mortalidade , Melanoma Amelanótico/patologia , Melanoma Amelanótico/fisiopatologia , Neoplasias Bucais/mortalidade , Neoplasias Bucais/patologia , Neoplasias Bucais/fisiopatologia , Análise de SobrevidaRESUMO
Melanomas são tumores agressivos de melanócitos que ocorrem principalmente na cavidade oral, nas junções mucocutâneas e na pele de cães. Este tipo de neoplasma pode apresentar diversos graus de pigmentação melânica, incluindo total ausência (melanomas amelanóticos [MA]). Os arquivos de biópsia do SPV-UFRGS, que compreendem o período de 2004 a 2010, foram revisados e levantados os casos de neoplasias melanocíticas em cães. Realizou-se estudo retrospectivo de 35 casos de MA e caracterização pela imuno-histoquímica (IHQ). As principais raças acometidas foram o Poodle, Dachshund e Cocker Spaniel, mas o maior número de casos foi observado em cães sem raça definida (SRD). A idade média desses cães foi de 10,7 anos (variação de 5 a 18 anos) e não houve predileção por sexo. As principais localizações incluíram cavidade oral (57,1%) e dígitos (17,1%). Histologicamente, 40% dos MA foram classificados como epitelioides, 34,3% como mistos e 25,7% como fusiformes. Na avaliação IHQ, 86,6% dos casos foram positivos para a vimentina, 70% para a proteína S-100 e 56,6% para o melan-A. Os resultados obtidos neste trabalho possibilitam concluir que os cães com MA caracterizavam-se por serem velhos. A forma celular mais observada foi a epitelioide. Devido a pouca diferenciação desses tumores, ressalta-se a importância da realização do painel imuno-histoquímico, sobretudo da proteína S-100, que apresentou melhor marcação que o melan-A.
Melanomas are aggressive tumors of melanocytes. They are common in dogs and involve mainly the oral cavity, mucocutaneous junction, and skin. Furthermore, these tumors could be highly pigmented or lack pigment. The biopsies archives from SPV-UFRGS, 2004 to 2010, were retrieved and melanocytic neoplasms in dogs were revised. A retrospective study of 35 cases of amelanotic melanomas (AM) was performed, also immunohistochemistry (IHC) characterization was evaluated. The dogs more affected were mixed breed followed by Poodle, Dachshund and Cocker Spaniel. The average age of the dogs was 10.7 years (5-18 years in age) and there was no sex predilection. The locations of the neoplasms were the oral cavity (57.1%) and digits (17.1%). Histologically, 40% were classified as epithelioid, 34.3% mixed and 25.7% spindle. The positive immunostaining for vimentin, S-100 protein and melan-A were 86.6%, 70%, and 56.6% respectively. These results indicated the most affected dogs with AM were elderly. Epiteliod classification was the most observed histologically. It is important to perform IHC, due to lacking of differentiation of AM, mainly, anti S-100 protein that showed to be the best option of positive marker, even better to Melan-A.
Assuntos
Animais , Idoso , Cães , Melanoma Amelanótico/diagnóstico , Melanoma Amelanótico/veterinária , Biópsia/veterinária , Células Epitelioides/patologia , Neoplasias/veterináriaRESUMO
Melanomas são tumores agressivos de melanócitos que ocorrem principalmente na cavidade oral, nas junções mucocutâneas e na pele de cães. Este tipo de neoplasma pode apresentar diversos graus de pigmentação melânica, incluindo total ausência (melanomas amelanóticos [MA]). Os arquivos de biópsia do SPV-UFRGS, que compreendem o período de 2004 a 2010, foram revisados e levantados os casos de neoplasias melanocíticas em cães. Realizou-se estudo retrospectivo de 35 casos de MA e caracterização pela imuno-histoquímica (IHQ). As principais raças acometidas foram o Poodle, Dachshund e Cocker Spaniel, mas o maior número de casos foi observado em cães sem raça definida (SRD). A idade média desses cães foi de 10,7 anos (variação de 5 a 18 anos) e não houve predileção por sexo. As principais localizações incluíram cavidade oral (57,1%) e dígitos (17,1%). Histologicamente, 40% dos MA foram classificados como epitelioides, 34,3% como mistos e 25,7% como fusiformes. Na avaliação IHQ, 86,6% dos casos foram positivos para a vimentina, 70% para a proteína S-100 e 56,6% para o melan-A. Os resultados obtidos neste trabalho possibilitam concluir que os cães com MA caracterizavam-se por serem velhos. A forma celular mais observada foi a epitelioide. Devido a pouca diferenciação desses tumores, ressalta-se a importância da realização do painel imuno-histoquímico, sobretudo da proteína S-100, que apresentou melhor marcação que o melan-A.(AU)
Melanomas are aggressive tumors of melanocytes. They are common in dogs and involve mainly the oral cavity, mucocutaneous junction, and skin. Furthermore, these tumors could be highly pigmented or lack pigment. The biopsies archives from SPV-UFRGS, 2004 to 2010, were retrieved and melanocytic neoplasms in dogs were revised. A retrospective study of 35 cases of amelanotic melanomas (AM) was performed, also immunohistochemistry (IHC) characterization was evaluated. The dogs more affected were mixed breed followed by Poodle, Dachshund and Cocker Spaniel. The average age of the dogs was 10.7 years (5-18 years in age) and there was no sex predilection. The locations of the neoplasms were the oral cavity (57.1%) and digits (17.1%). Histologically, 40% were classified as epithelioid, 34.3% mixed and 25.7% spindle. The positive immunostaining for vimentin, S-100 protein and melan-A were 86.6%, 70%, and 56.6% respectively. These results indicated the most affected dogs with AM were elderly. Epiteliod classification was the most observed histologically. It is important to perform IHC, due to lacking of differentiation of AM, mainly, anti S-100 protein that showed to be the best option of positive marker, even better to Melan-A.(AU)