espanolEl objetivo de este trabajo fue estudiar los aspectos clinicos, histopatologicos e histoquimicos del melanoma cutaneo (MC) en caballos (Equus ferus caballus) del Departamento de Cordoba, Colombia. Dicho estudio fue de tipo descriptivo, no probabilistico, en caballos de conveniencia. Se utilizaron 24 caballos provenientes de diferentes explotaciones ganaderas, con diagnostico clinico e histopatologico de MC. Al describir las lesiones, se observaron masas nodulares infiltrativas o con apariencia de placas, de tamanos variados, de consistencia firme, exofiticas, pigmentadas, alopecicas y, en algunos casos, con ulceraciones en la piel. Sin embargo, los tejidos adyacentes (oseos o musculares) no fueron invadidos por las lesiones. Las lesiones estaban localizadas en la superficie ventral de la cola, regiones perianal, perineal, genital (vulva, prepucio y pene), cuello, parpados y comisuras labiales de los animales estudiados. El analisis histopatologico con la coloracion de hematoxilina-eosina, revelo la presencia de celulas de tamano variable; asi mismo, los nucleos diferian entre las celulas y se observaron figuras mitoticas. El tipo celular mas observado fueron las celulas epiteliodes, pleomorficas y redondas. Las areas tumorales estaban difusamente definidas y fuertemente pigmentadas, observandose la presencia de grandes cantidades de melanocitos atipicos agrupados (en nidos o tecas). Con la coloracion de tricromico de Gomori, se observo escasa proliferacion dermica de colageno desorganizado, con escasa presencia de tejido conjuntivo difuso, mientras que, con la tecnica de microscopia de polarizacion, utilizando la coloracion de rojo picrosirius, se observaron areas de birrefringencia rojiza, indicando moderada presencia de colageno maduro tipo I (color rojo brillante en la polarizacion). El diagnostico definitivo de la enfermedad, se fundamento en las caracteristicas clinicas, el diagnostico diferencial y los hallazgos histopatologicos, siendo concluyentes como metodos de diagnostico del MC, constituyendo el primer reporte de esta enfermedad en caballos del Departamento de Cordoba de Colombia. EnglishThe aim of this study was to evaluate the clinical, histological, and histochemical aspects of cutaneous melanoma (CM) in convenience horses (Equus ferus caballus) of the Department of Cordoba, Colombia. The study was descriptive, non-probabilistic. A total of 24 horses from different farms, with clinical and histopathologic diagnosis of MC, were used. In describing the lesions, infiltrating or plate-appearance, firm, exophytic, pigmented, and alopecic tumor masses, were observed and; in some cases, skin ulcerations were seen. However, the adjacent tissues (bone or muscle) were not invaded by injuries. The lesions were located in the ventral surface of the tail, the perianal, perineal, and genital regions (vulva, foreskin, and penis), neck, eyelids, and labial commissures of the animals studied. Histological examination with hematoxylin staining-eosin revealed the presence of cells of variable size; similarly, the nuclei were different between cells and mitotic figures were observed. Most of the observed cell types were: epithelioid, pleomorphic, and round cells. Tumor areas were vaguely defined and highly pigmented, showing the presence of large amounts of grouped atypical melanocytes (in nests or teak). With trichrome Gomori staining, poor dermal proliferation of disorganized collagen was observed, with scarce presence of diffuse connective tissue, whereas with the polarization microscopy technique, which uses picrosirius red staining, areas of red birefringence were observed, indicating moderate presence of mature type I collagen (bright red color in polarization). The definitive diagnosis of MC was based on clinical features, differential diagnosis, and histopathologic findings. These were conclusive diagnostic methods for MC, becoming the first report of this disease in horses of the Cordoba Department, Colombia.