Neoplasias melanocíticas cutâneas em cães: aspectos clínicos e histopatológicos em 58 casos / Cutaneous melanocytic neoplasms in dogs: aspects clinics and histopathologics in 58 cases

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

Thirty nine cases (42 lesions) of melanocytoma and nineteen cases (19 lesions) of canine cutaneous melanoma were analyzed clinic and histopathologically. The melanocytomas affected the young animals as well as the old ones, without a sexual predisposition. The most affected dogs were the ones of the Schnauzer and Doberman breed, being followed by those without a defined breed. Most lesions appeared solitarily and located in the eyelid, interdigital and thoraxes regions. Generally, the lesions were papuled, no haired, non adhering, black colored, with a firm consistency and a mean diameter of 1,2 cm. Recurrence and metastases were not seen. Such fact confirms the good prognostic associated to melanocytomas. Histopathologically, was observed that the dermal sub-type was the most frequent. There was no significant difference among the various regions affected by the dermal and compound melanocytomas. Four cell types were observed, with most lesions showing a combination of fusiform and big round cells. The cells presented different modes of arrangements and, the most observed was the solid, associated or not with the teaks. Collagenous bars, not very cellular, more eosinofilic, dense and hialin than the normal, composed the stroma. The benign biological behavior of melanocytomas corresponded to the histological appearance. The melanomas affected the older animals, without a sexual predisposition. The most affected dogs were the ones without a defined breed, being followed by those of the Rottweiler, Pinscher, Cocker Spaniel and Airedale breed. The lesions appeared solitarily and located on the lips and eyelid. Most tumors were ulcerated and nodular, with a firm consistency, with a mean diameter of 2,5cm. Some lesions presented recurrence. Metastases could not be proven. Among the cases with a known clinical segment, some were cured through a surgical procedure, however, the majority died, probably related to a neoplasm disease, confirming the bad prognostic related to melanoma. Histopathologically, lesions with dermal and junction activities were observed, being the pagetoid infiltration a not frequent finding. Four cell types were observed, however, the fusiforms and epithelioid groupings were the most frequent. The cell presented different modes of arrangements, but the solid, associated or not to teaks, was the most observed. The stroma came, most of the times, scarce, not very cellular, desmoplastic and with discreet collagenous bars. The histopathology analysis could predict approximately 60% of the melanoma malign behavior.

ASSUNTO(S)

cão pele tumores clinica veterinaria melanoma cutâneo dogs cutaneous melanoma

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