Feline cutaneous viral papilloma associated with human papillomavirus type 9.

A 12-year-old domestic Shorthaired cat developed a multinodular exophytic mass on the dorsal surface of the nose. The skin surrounding the mass was nonpigmented, and actinic keratosis had been diagnosed in this area 3 years previously. Histologic examination revealed hyperkeratosis, epidermal hyperplasia, papillomatosis, koilocytosis, and possible intranuclear viral inclusions. Polymerase chain reaction amplified papillomaviral deoxyribonucleic acid from formalin-fixed samples of the lesion. Sequencing of the amplicon revealed 98% similarity to human papillomavirus (HPV) type 9. To the authors' knowledge, this is only the second reported feline cutaneous viral papilloma. In addition, this is the first report of a feline papilloma being associated with an HPV.