Papillomas are benign growths caused by the canine papillomavirus (see Papillomas). The oral mucosa and commissures of the lip are most frequently involved, but the growths (usually multiple but sometimes single) can involve the palate and oropharynx. Papillomas are most common in young dogs and appear suddenly, with rapid growth and spread. Signs are seen when the growths interfere with prehension, mastication, or swallowing. Occasionally, if the growths are numerous, the dog may bite them when chewing, causing them to bleed and become infected. They may regress spontaneously within a few weeks to months, and removal is generally not necessary. If necessary, the exophytic lesion can be debulked with electro- or radiosurgery or by sharp resection. Surgical removal of one or more of the papillomas may initiate regression. The use of commercial or autogenous vaccines should be considered in very severe cases in which the dog cannot swallow or breathe normally. The self-limiting character of the disease makes evaluation of any treatment difficult. Severe oral papillomatosis may be seen in immunocompromised dogs with lymphoma.
Other wart-like lesions are benign exophytic proliferations of squamous epithelium. They are clinically indistinguishable from virus-induced papillomas but are generally slow growing and solitary. They most commonly remain benign, and surgical removal is curative.