Penile neoplasm associated with Equus caballus papillomavirus type 2 infection in a miniature Appaloosa

An 18-year-old miniature Appaloosa stallion presented with 6 months of history of sanguineous crusts on medial hind limbs and discomfort of micturition. Cauliflower-like and small masses were treated with cryotherapy for 6 months, but the regrowth of masses occurred. Subsequently, local excision via laser and topical treatment with 5% 5-fluorouracil for 5 months were followed. However, the horse was euthanized 4 months later due to regrowth of the masses. The mass was diagnosed as penile papilloma with cellular atypia and Equus caballus papillomavirus type 2 (EcPV-2) DNA was detected. This is the first report of equine penile neoplasm with EcPV-2 infection in Asia.