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O dano capilar causado pelo descolorimento oxidativo é muito intenso, sendo que dois fatores são responsáveis por essa ação: primeiro, a ação direta e danosa do oxidante em diversas estruturas capilares e segundo, o dano oxidativo primário facilita o dano causado por outros agentes físicos (luz, temperatura) e químicos (tensoativos), que comumente tem ação nos cabelos. Desenvolver conceitos e tecnologias que possam tornar o oxidante específico para a melanina e por conseguinte efetuando o descolorimento sem causar danos ao fio é extremamente desejável. Neste trabalho buscaremos entender de que forma a luz visível pode aumentar a ação do oxidante sem danificar o fio colateralmente. O objetivo principal deste trabalho é demonstrar que é possível utilizar a luz visível, que é absorvida pela melanina, para tornar esse pigmento mais suscetível ao agente oxidante e desta forma, permitir que o descolorimento seja realizado com concentrações pequenas de oxidante. Também almejamos desenvolver métodos de análises por microscopia ótica de fluorescência e de reflexão para mensurar o dano nas estruturas dos fios processados com oxidante e na presença ou ausência da luz

The capillary damage caused by oxidative discoloration is very intense, and two factors are responsible for this action: first, the direct and harmful action of the oxidant on several capillary structures and second, the primary oxidative damage facilitates the damage caused by other physical agents (light, temperature) and chemicals (surfactants), which commonly have action on the hair. Developing concepts and technologies that can make the oxidant specific to melanin and therefore discoloring without causing damage to the hair is extremely desirable. In this work we will try to understand how visible light can increase the oxidant's action without damaging the wire collaterally. The main objective of this work is to demonstrate that it is possible to use visible light, which is absorbed by melanin, to make this pigment more susceptible to the oxidizing agent and, thus, to allow the discoloration to be carried out with small concentrations of oxidizer. We also aim to develop methods of analysis by optical fluorescence and reflection microscopy to measure the damage to the structures of the threads processed with oxidizer and in the presence or absence of light

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O albinismo é uma desordem genética recessiva em que a produção de melanina é reduzida ou ausente, o que interfere na pigmentação da pele, pelos e olhos dos indivíduos. É considerada de rara ocorrência natural, principalmente em animais selvagens. Indivíduos albinos são altamente suscetíveis a injúrias na pele causadas pelo sol, já que a exposição aos raios ultravioletas (UV) de forma cumulativa pode ser prejudicial. Este relato discorre sobre a ocorrência de seborreia seca em uma anta albina (Tapirus terrestris), mantida sob cuidados humanos. A seborreia seca é uma enfermidade cutânea de caráter crônico em que ocorre falha na queratinização da epiderme, formando excessivamente escamas e alterando a oleosidade da pele e pelos. O tratamento clínico instituído foi baseado na aplicação tópica de solução dermatológica hidratante spray e em mudanças realizadas no recinto a fim de diminuir a incidência de luz solar no indivíduo. O resultado foi satisfatório e teve como auxílio um microscópio digital portátil que foi utilizado periodicamente até a recuperação do animal.(AU)

Albinism is a recessive genetic disorder in which melanin prodution is reduced or absent, interfering with pigmentation of the skin, hair and eyes of individuals. It is considered to be of rare natural occurrence, mainly in wild animals. Albino individuals are highly susceptible to skin damage caused by the sun, once cumulative exposure to ultraviolet (UV) rays can be harmful. This report discusses the occurrence of dry seborrhea in an albino lowland tapir (Tapirus terrestris), kept under human care. Dry seborrhea is a chronic skin disease in which there is a failure in the keratinization of the epidermis, forming excessive scales and altering the oiliness of the skin and hair. The clinical treatment instituted was based on topical application of a moisturizing dermatological spray solution and on changes made to the enclosure in order to reduce the incidence of sunlight on the individual. The result was satisfactory and had as na aid a portable digital microscope that was used periodically until the recovery of the animal.(AU)

El albinismo es una anomalía genética recesiva en la que la produccíon de la melanina está reducida o ausente, lo que interfiere com la pigmentación de la piel, pelaje y los ojos de los individuos. Se considera un fenómeno natural raro, principalmente en animales salvajes. Los albinos son muy susceptibles al daño de la piel por el sol, ya que la exposición acumulada a los rayos ultravioleta (UV) puede ser dañina. Este reporte discute la ocurrencia de seborrea seca en un tapir albino (Tapirus terrestris), mantenida bajo cuidado humano. La seborrea seca es una enfermedad crónica de la piel en la que falla la queratinización de la epidermis, formándose descamaciones excesivas y alterando la oleosidad de la piel y la pelaje. El tratamiento clínico instituido se basó en la aplicación tópica de uma solución dermatológica hidratante en spray y em la modificación del recinto para reducir la incidencia de la luz solar sobre el individuo. El resultado fue satisfactorio y tuvo como ayuda un miscroscopio digital portátil que se utilizó periódicamente hasta la recuperación del animal.(AU)

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Resumen En alpacas los fenotipos del color de vellón tienen diferentes terminologías que induce a una confusión dentro del color marrón y sus tonalidades, el que requiere de una mejor descripción y cuantificación. En consecuencia los objetivos del estudio fueron cuantificar el color de fibra e identificar los PNSs informativos del gen MC1R (receptor 1 de melanocortina) en alpacas marrones y negras. Un fenotipo vicuña (n=14) y cuatro fenotipos de alpacas (n=79), marrón claro, marrón oscuro, marrón-negro y negro fueron evaluados por colorimetría. El vellón de vicuña mostró mayor luminosidad (47.74) e intensidad de color (24.33) respecto a las alpacas marrones. Los valores obtenidos de CIE L*a*b* (luminosidad e intensidad) sugieren valores bajos en alpacas eumelánicas y altos en alpacas feomelánicas. En vicuña y alpaca la secuencia codificante del gen MC1R tiene un solo exón de 954 pb, las vicuñas no mostraron la deleción (c.224_227del). Sin embargo, esta deleción se ha observado en los tres fenotipos de alpaca (marrón claro, marrón oscuro y negro), al igual que los cinco PNSs no sinónimos que ya fueron descritos en otras poblaciones, c.82A>G, c.259G>A, c.376G>A, c.587T>C, c.901C>T (p.T28A, p.M87V, p.G126S, p.F196S y p.R301C). Para las dos especies, se identificaron un total de ocho haplotipos definidos por los cinco PNSs. No se observaron asociaciones entre los fenotipos de color y los PNSs: c.259G>A, c.376G>A y c.901C>T (p>0.05), probablemente debido a la influencia de otros genes como el ASIP en la expresión del color. Nuestros resultados, así como los estudios previos evidenciaron regiones altamente conservadas en la secuencia codificante del gen MC1R.

Abstract In alpacas color fleece phenotypes have different terminologies that induces confusion within the brown color and its shades, it requires a better description and quantification. Consequently, the aims of the study were to quantify the color of fiber and identify the informational SNPs in the MC1R gene (melanocortin 1 receptor) in brown and black alpacas. A vicuña phenotype (n=14) and four alpaca phenotypes (n=79), light brown, dark brown, brown-black and black were evaluated by colorimetry. The vicuña fleece showed greater lightness (47.74) and color intensity (24.33) compared to brown alpacas. The CIE L*a*b* values (lightness and intensity) suggest low values in eumelanic alpacas and high in pheomelanic alpacas. In vicuña and alpaca, the coding sequence of the MC1R gene has a single exon of 954 bp, in vicuñas the deletion (c.224_227del) was not observed. However, this deletion was observed in three alpaca phenotypes (light brown, dark brown and black), as well as the five non-synonymous SNPs described in other populations, c.82A>G, c.259G>A, c.376G>A, c.587T>C, c.901C>T (p.T28A, p.M87V, p.G126S, p.F196S, and p.R301C). Eight haplotypes defined by the five SNPs were identified in both species. The associations between color phenotypes and SNPs were not observed (p>0.05), probably due to the influence of other genes such as ASIP on color expression. Our results as well as previous studies showed highly conserved regions in the coding sequence of the MC1R gene.

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Background: Melanosis is a blackened pigmentation resulting from the accumulation of melanocytes in tissues that are not normally pigmented. This change in the color of the organs occurs due to the agglomeration of melanocytes originating from abnormal migration during embryogenesis and does not cause dysfunction to the affected organ. Although melanosis frequently occurs in several species and affects several organs such as the brain and spinal cord leptomeninges, involvement in the thalamus region is unusual. The objective of this work was to report 2 cases of thalamic melanosis in goats, determining the pathological and histochemical aspects that assist in the diagnosis of this condition. Cases: Two cases of thalamic melanosis in goats were diagnosed. In both cases, the animals had no nervous history disease and clinical signs. The cause of death in cases 1 and 2 was established based on anatomopathological findings and clinical signs being diagnosed with mycoplasmosis and asphyxia, respectively. After fixing and making cross-sections of the brain, a focal lengthy blackened area was observed on the thalamus surface in both cases. Microscopically, lesions in the brain were similar in both cases and exclusively affected the thalamus. These cells had abundant cytoplasm, well delimited with brownish granular pigment. The nuclei were difficult to visualize and in some cells, it was rounded, well-defined, morphologically compatible with melanocytes. Melanocytes were mainly distributed around neurons and often distended the perivascular space of multiple blood vessels. In Fontana Masson staining, the granules in the cytoplasm of these cells stained strongly black. The Prussian Blue, Periodic Acid- Schiff's, Von Kossa, and Giemsa stains were negative, and the pigment remained brown. In the unstained slides, assembled after the deparaffinization and clarification process, it was observed the permanence of cells with blackish-brown pigment in the cytoplasm. In immunohistochemistry, strong immunostaining of pigmented cells with the Anti-MelanA antibodies was observed in both cases. Discussion: The diagnosis of thalamic melanosis in goats was carried out based on the characteristic pathological findings, in which melanin pigments were demonstrated and identified through HE, Fontana-Masson staining, and unstained slides and confirmed by the IHC. The use of complementary histochemical techniques was fundamental for the classification of the pigment as melanin, demonstrating to be an accessible and reliable tool for the diagnosis of pathological processes that lead to the accumulation of pigments and or material in the tissues. The occurrence of melanin in the thalamus may be associated with a failure in the migration of melanoblasts, which would go to the optical pathways or to the thalamus. This erratic migration of melanoblasts can be explained by the fact that the forebrain is the embryogenic origin of the optic and diencephalon pathways. Macroscopically, thalamic melanosis must be differentiated mainly from neoplastic processes such as melanoma and hemangiosarcoma, pigmented fungus infections, Phalaris angusta poisoning, listeriosis, neurocutaneous melanosis, and neuromelanin. It was concluded that thalamic melanosis is an uncommon alteration in goats and although it has been diagnosed as an incidental necropsy finding, should be included in the differential diagnosis of diseases that affect the central nervous system, especially those that have a color change associated with the deposition of pigments in the tissues.

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SUMMARY: Human skin melanin was stained using the Fontana's silver nitrate method and Schmorl method. The results showed that, in the Fontana's silver nitrate method, melanin and silver-bound cells were black and other tissues were red. When stained using the Schmorl method, effects on melanin differed based on whether the nuclei were stained. When the nucleus was stained, melanin appeared blue-black or blue-green, and other tissue structures were purple. When the nucleus was not stained, melanin was orange and other structures were pink. Comparing the two staining methods, we concluded that Fontana's silver nitrate method takes a long time; in contrast, the Schmorl method showed two different types of results depending on whether the nucleus was stained, and it takes less time than Fontana staining, so we here consider the Schmorl method more suitable for special staining of melanin than Fontana's silver nitrate method.

RESUMEN: La melanina de la piel humana se tiñó utilizando el método del nitrato de plata de Fontana y el método Schmorl. Los resultados mostraron que, en el método del nitrato de plata de Fontana, la melanina y las células unidas a plata eran negras y otros tejidos eran rojos. Cuando se tiñó con el método de Schmorl, los efectos sobre la melanina difirieron en función de si se tiñeron los núcleos. Cuando se tiñó el núcleo, la melanina apareció de color azul-negro o azul-verde, y otras estructuras de tejido fueron de color púrpura. Cuando el núcleo no estaba teñido, la melanina era naranja y otras estructuras eran rosadas. Al comparar los dos métodos de tinción, llegamos a la conclusión de que el método del nitrato de plata de Fontana lleva mucho tiempo; por el contrario, el método Schmorl mostró dos tipos diferentes de resultados dependiendo de si el núcleo estaba teñido, y lleva menos tiempo que la tinción de Fontana, por lo que aquí consideramos que el método Schmorl es más adecuado para la tinción especial de melanina que el método del nitrato de plata de Fontana.

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Resumen: Las lesiones del ángulo pontocerebeloso (APC) representan el 6 al 10% de las neoplasias intracraneales, siendo los schwannomas vestibulares y meningiomas los más comunes. Sin embargo, hasta el 15% pueden ser otras lesiones, entre ellas las derivadas a partir de restos de células melanocíticas presentes en las leptomeninges. El diagnóstico diferencial de las patologías tumorales del APC es extenso, siempre teniendo en cuenta las lesiones más comunes. Sin embargo, cuando las características radiológicas no son las esperadas, el enfoque debe orientarse hacia las lesiones inusuales, poniendo en contexto las diferentes estirpes celulares que pueden dar origen a las neoplasias en esta localización, como las neoplasias melanocíticas. Se presenta el caso de un masculino de 74 años con síndrome cerebeloso de tórpida evolución, al cual se le realiza RM de cerebro contrastada, identificando una lesión de base dural en el APC izquierdo, con hiperintensidad de señal en T1 e hipointensidad en T2, atípico para las lesiones más comunes en esta región, que sugiere su contenido melanocítico.

Abstract: Cerebellopontine angle tumors (CPA) represent approximately 6 to 10% of intracranial tumors. Vestibular Schwannomas and meningiomas are the most common, however up to 15% can be of other origin, including from melanocytes derived from the neural crest. The differential diagnosis of CPA pathologies is extensive, always taking into account the most common ones. However, if the radiological characteristics are not the expected, the approach should be directed towards unusual lesions, putting into context the different cell lines that can give rise to the neoplasm at this location, such as melanotic neoplasms. We present a case of a 74-year-old male, who presented with a cerebellar syndrome. Due to an atypical clinical evolution, a contrast enhanced head MRI was performed, revealing a dural based tumor on the left CPA, which was hyperintense on T1 and hypointense on T2 weighted sequences, which is not expected from the common lesions at this region and suggested it's melanotic content.

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ABSTRACT Organisms with source-populations restricted to the subterranean biotope (troglobites) are excellent models for comparative evolutionary studies, due to their specialization to permanent absence of light. Eye and dark pigment regression are characteristics of most troglobites. In spite of the advance in knowledge on the mechanisms behind eye regression in cave fishes, very little is known about pigmentation changes. Studies were focused on three species of the genus Pimelodella. Exemplars of the troglobitic P. spelaea and P. kronei were compared with the epigean (surface) P. transitoria, putative sister-species of the latter. Melanophore areas and densities are significantly lower in the troglobitic species. Evaluating the in vitro response of these cells to adrenaline, acetylcholine and MCH, we observed a reduced response in both troglobites to adrenaline. The same trend was observed with MCH, but not statistically significant. No response to acetilcholine was detected in all the three. Contrary to expectations, even though eye-regression in P. spelaea was much lower than in P. kronei, pigmentation regression was more advanced. Multiple mechanisms of loss showing a mosaic of traits in troglobitic fishes are discussed here.

RESUMO Organismos com populações-fonte restritas ao biótopo subterrâneo (troglóbios) são excelentes modelos para estudos evolutivos comparativos, devido à especialização resultante do isolamento sob um regime seletivo particular, com ênfase na permanente falta de luz. A regressão do olho e da pigmentação são características dos troglobites. Apesar do avanço do conhecimento sobre os mecanismos subjacentes à regressão ocular em peixes de caverna, pouco se sabe sobre mudanças de pigmentação. Os estudos foram focados em três espécies do gênero Pimelodella. Exemplares das espécies troglóbias P. spelaea e P. kronei foram comparados com a epígea P. transitoria, provável espécie-irmã dessa última. As áreas e densidades dos melanóforos são significativamente menores nas espécies troglóbias. Avaliando a resposta in vitro dessas células à adrenalina, acetilcolina e MCH, observamos uma resposta reduzida em ambos os troglóbios à adrenalina. A mesma tendência foi observado com o MCH, mas não estatisticamente. Nenhuma resposta à acetilcolina foi detectada três. Contrariamente às expectativas, embora a regressão ocular em P. spelaea seja bem menor do que em P. kronei, a regressão na pigmentação foi mais acentuada. Múltiplos mecanismos de regressão, mostrando um mosaico de características em peixes troglóbios, são discutidos aqui.

RESUMO

Organisms with source-populations restricted to the subterranean biotope (troglobites) are excellent models for comparative evolutionary studies, due to their specialization to permanent absence of light. Eye and dark pigment regression are characteristics of most troglobites. In spite of the advance in knowledge on the mechanisms behind eye regression in cave fishes, very little is known about pigmentation changes. Studies were focused on three species of the genus Pimelodella. Exemplars of the troglobitic P. spelaea and P. kronei were compared with the epigean (surface) P. transitoria, putative sister-species of the latter. Melanophore areas and densities are significantly lower in the troglobitic species. Evaluating the in vitro response of these cells to adrenaline, acetylcholine and MCH, we observed a reduced response in both troglobites to adrenaline. The same trend was observed with MCH, but not statistically significant. No response to acetilcholine was detected in all the three. Contrary to expectations, even though eye-regression in P. spelaea was much lower than in P. kronei, pigmentation regression was more advanced. Multiple mechanisms of loss showing a mosaic of traits in troglobitic fishes are discussed here.(AU)

Organismos com populações-fonte restritas ao biótopo subterrâneo (troglóbios) são excelentes modelos para estudos evolutivos comparativos, devido à especialização resultante do isolamento sob um regime seletivo particular, com ênfase na permanente falta de luz. A regressão do olho e da pigmentação são características dos troglobites. Apesar do avanço do conhecimento sobre os mecanismos subjacentes à regressão ocular em peixes de caverna, pouco se sabe sobre mudanças de pigmentação. Os estudos foram focados em três espécies do gênero Pimelodella. Exemplares das espécies troglóbias P. spelaea e P. kronei foram comparados com a epígea P. transitoria, provável espécie-irmã dessa última. As áreas e densidades dos melanóforos são significativamente menores nas espécies troglóbias. Avaliando a resposta in vitro dessas células à adrenalina, acetilcolina e MCH, observamos uma resposta reduzida em ambos os troglóbios à adrenalina. A mesma tendência foi observado com o MCH, mas não estatisticamente. Nenhuma resposta à acetilcolina foi detectada três. Contrariamente às expectativas, embora a regressão ocular em P. spelaea seja bem menor do que em P. kronei, a regressão na pigmentação foi mais acentuada. Múltiplos mecanismos de regressão, mostrando um mosaico de características em peixes troglóbios, são discutidos aqui.(AU)

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Objective: The present study aimed to explore the prevalence of melanin pigmentation in a sample of Yemeni population and its relation to some possible risk factors. Material and Methods: This crosssectional study was performed on 440 patients attending a private clinic. Printed questionnaires were introduced to the patients and a clinical examination was performed for each patient. The questionnaire included questions regarding demographic data, and questions regarding some common habits such as smoking, khat chewing and consuming of hot drinks. Melanin pigmentation was assessed regarding its presence, most affected areas and the numbers of affected quadrants. The data were managed and analyzed using SPSS software program. Descriptive statistics and inferential statistics were performed and the associations of melanin with risk factors were evaluated at P value < 0.05. Results: Four hundred and forty patients with mean age 29 ± 8.21 years were included in the study. Of them, 67.5% were fair-skinned, 26.8% were smokers, 48.2% were khat chewers and 33.6% were hot drinks consumers. The prevalence of melanin pigmentation was 62.7%, with class I represented 56.5% of cases. Males showed more prevalence (67.9%) of melanin pigmentation than females (57.7%) with no significant difference. Results also showed more prevalence of melanin pigmentation in patients > 25 years, and darkskinned patients. Regarding habits, smoking, khat chewing and hot drink consumption habits showed significant associations with melanin pigmentation. Whereas the association of khat chewing and hot drinks alone with melanin pigmentation showed no significant relationship with melanin pigmentation while, the merge effects of khat chewing and smoking habits together with melanin pigmentation showed significant relationship with melanin pigmentation. Conclusion: It can be concluded that Yemeni people had high prevalence of melanin pigmentation with more prevalence of CL I type. Males, patients > 25 years and dark-skinned patients showed more prevalence of melanin pigmentation. Smoking, khat chewing and hot drinks consuming habits had significant associations with melanin pigmentation.(AU)

Objetivo: O presente estudo teve como objetivo explorar a prevalência de pigmentação da melanina em uma amostra da população iemenita e sua relação com alguns possíveis fatores de risco. Material e Métodos: Trata-se de um estudo transversal com 440 pacientes atendidos em uma clínica particular. Cada paciente respondeu a um questionário impresso e passou por um exame clínico. O questionário incluía perguntas sobre dados demográficos e questões sobre alguns hábitos comuns, como fumar, mastigar khat e consumir bebidas quentes. A pigmentação da melanina foi avaliada quanto à presença, áreas mais afetadas e número de quadrantes afetados. Os dados foram gerenciados e analisados no programa SPSS. Foi realizada estatística descritiva e inferencial e as associações de melanina com fatores de risco foram avaliadas com valor de p 25 anos e pacientes de pele escura. Quanto aos hábitos, tabagismo, mascar khat e consumo de bebida quente apresentaram associação significativa com a pigmentação da melanina. Enquanto a associação de mascar khat e bebidas quentes isoladamente não mostrou relação significativa com a pigmentação de melanina, enquanto os efeitos da associação dos hábitos de mascar e fumar khat juntamente com pigmentação por melanina mostraram relação significativa com a pigmentação por melanina. Conclusão: Pode-se concluir que o povo iemenita apresentou alta prevalência de pigmentação por melanina, com maior prevalência do tipo CL I. Homens, pacientes> 25 anos e pacientes de pele escura apresentaram maior prevalência de pigmentação da melanina. O hábito de fumar, mascar khat e consumir bebidas quentes teve associações significativas com a pigmentação da melanina. (AU)

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Resumen El carcinoma de células escamosas (CCE) es la neoplasia más frecuente en los bovinos. El trabajo determinó la frecuencia del CCE y factores de riesgo asociados desde el año 2007 hasta el 2019, en el departamento de Nariño. Se analizaron 82 casos de la base de datos de la clínica de animales grandes de la Universidad de Nariño, teniendo en cuenta las variables: raza, edad, número de partos, ubicación del tumor, pigmentación de la piel y la altura sobre el nivel del mar de las fincas. Posteriormente, se formaron tres grupos: < 3 años (jóvenes), entre 4 y 7 años (adultos) y > 8 años (seniles). Las 56 fincas están ubicadas a 2973 ± 197.01 metros sobre el nivel del mar (msnm). Las razas estudiadas fueron: Holstein 81.2 %, Normando 7.2%, Montbeliarde 3.4 %, Simhol 3.4 %, Criollas 2.4 %, Jersey 1.2 % y Cebú 1.2 %. La presentación de CCE comprometía en su mayoría, la región ocular y periorbital 85.3 %, seguida de vulva 11.1 % y entre el dorso, ubre y cuerno en un 3.9 %. La despigmentación de la piel se presentó en 31.7 % de los casos. El promedio de edad fue 7.7 ± 1.58 años; dos novillas, 58 adultos y 22 seniles con un promedio de 4.7 ± 1.35 partos. La frecuencia de presentación fue significativamente mayor en animales adultos (p < 0.001). La ubicación del carcinoma fue mayor en el ojo y en el tejido periorbital (p < 0.005), la presentación fue significativa en animales con áreas de piel no pigmentada y en la raza Holstein (p < 0.005 y p < 0.001 respectivamente). Se determinó como factor de riesgo la edad, la despigmentación y la altitud (msnm) de las fincas. El estudio representa el primer reporte de ocurrencia y factores asociados al CCE en bovinos, en el Departamento de Nariño.

Abstract Squamous Cell Carcinoma (SCC) is the most frequent neoplasia in bovines. This work determined the SCC frequency and the associated risk factors from 2007 to 2019 in Nariño Province. Eighty-two cases from the big animal clinic database at the Universidad de Nariño were analyzed. The variables considered herein include: breed, age, parity, tumor location, skin pigmentation and MASL of the farms. Three groups were created: < 3 years old (younger), from 4 to 7 years old (adults), and > 8 years old (elder). The 56 farms are located at 2973 ± 197.01 meters above sea level. The studied breeds include Holstein 81.2%, Normando 7.2%, Montbeliarde 3.4%, Simhol 3.4%, Criollas 2.4%, Jersey 1.2% and Cebú 1.2%. the SCC compromised the eye and periorbital regions in 85.3% of the cases, followed by the vulva 11.1%, and 3.9% in the back, udder and horns. Skin depigmentation was observed in 31.7% of the cases. The average age was 7.7 ± 1.58 years; 2 heifers, 58 adults and 22 elders with a parity of 4.7 ± 1.35 on average. Appearance frequency was significantly higher in adult animals (p<0,001). The location of the carcinoma was greater in the eye and the periorbital tissue (p<0,005). The appearance was significantly higher in animals with non-pigmented skin areas and in the Holstein breed (p<0.005 and p<0.001, respectively). The risk factors found in this research were age, depigmentation and MASL of the farms. This study is the first report of occurrence and factors associated with the SCC in bovines in the Nariño Province.

Resumo O carcinoma de células escamosas (CEC) é a neoplasia mais comum em bovinos. O trabalho determinou a frequência da CCE e os fatores de risco associados de 2007 a 2019, no departamento de Nariño. Foram analisados ​​82 casos a partir do banco de dados da clínica de grandeis animais da Universidade de Nariño, considerando as variáveis: raça, idade, número de partos, localização do tumor, pigmentação da pele e altura acima do nível de mar das fazendas. Três grupos foram formados : <3 anos (jovens), entre 4 e 7 anos (adultos) e> 8 anos (senis). As 56 fazendas estão localizadas a 2973 ± 197,01 metros sobre o nível do mar (msnm). As raças estudadas foram: Holstein 81,2%, Normando 7,2%, Montbeliarde 3,4%, Simhol 3,4%, Crioulo 2,4%, Jersey 1,2% e Cebu 1,2%. A apresentação da CCE comprometeu principalmente a região ocular e periorbital em 85,3%, seguida pela vulva em 11,1% e entre as costas, úbere e corno em 3,9%. A despigmentação da pele ocorreu em 31,7% dos casos. A idade média foi de 7,7 ± 1,58 anos; duas novilhas, 58 adultos e 22 senis, com média de 4,7 ± 1,35 partos. A frequência de apresentação foi significativamente maior em animais adultos (p <0,001). A localização do carcinoma foi maior no olho e no tecido periorbital (p <0,005), a apresentação foi significativa em animais com áreas de pele não pigmentada e na raça Holstein (p <0,005 e p<0,001, respectivamente). A idade, despigmentação e altitude (msnm) das fazendas foram determinadas como fator de risco. O estudo representa o primeiro relato de ocorrência e fatores associados à CCE em bovinos, no Departamento de Nariño.