Solitary Pedunculated Multicystic Viral Plaque Associated with Canine Papillomavirus 18 in a British Bulldog

A solitary pedunculated multicystic viral plaque was identified on the rump of an 8-year-old British Bulldog, associated with canine papillomavirus 18 (CPV18). This case is unique as viral plaques in dogs are typically multiple and sessile, not solitary and exophytic. Histology revealed numerous keratin-filled cystic cavities, and CPV18 DNA was confirmed via PCR. The mass was initially suspected to be a hair follicle tumor but was diagnosed as a viral plaque due to its histological features. This case expands the known clinical presentations of viral plaques in dogs and highlights the importance of differentiating between viral plaques and hair follicle tumors. The mass did not recur three months post-excision, and no additional lesions developed.