Atypical villonodular synovitis in a horse.
A 4-year-old sexually intact male Standardbred trotter was evaluated for left forelimb lameness. A presumptive diagnosis of severe cartilage damage was made because the horse had a history of infectious arthritis involving the left metacarpophalangeal joint. Arthroscopic evaluation revealed what was presumed to be a large villonodular lesion. The mass was surgically removed, and the horse was treated with procaine penicillin G, trimethoprim-sulfamethoxazole, phenylbutazone, and polysulfated glycosaminoglycans and eventually returned to racing. Histologic examination of the mass revealed a bed of granulation tissue covered with keratinized epithelium. We hypothesize that the lesion developed secondarily to implantation of epithelial cells into a reactive villonodular lesion.
Vickers
K L
KL
Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Kennett Square 19348-1692, USA.
Ross
M W
MW
D000818:Animals; D005552:Forelimb; D006734:Horse Diseases / Q000473:pathology* / Q000601:surgery; D006736:Horses; D008297:Male; D013586:Synovitis, Pigmented Villonodular / Q000473:pathology / Q000601:surgery / Q000662:veterinary*