Detection of DNA sequences from a novel papillomavirus in a feline basal cell carcinoma.

BACKGROUND: Basal cell carcinomas (BCCs) are uncommon feline skin neoplasms of uncertain cause.

CASE: A 14-year-old Abyssinian cat developed a soft dermal nodule on the dorsal thorax. This mass grew slowly over a six month period before being surgically excised.

METHODS AND RESULTS: Histology revealed a BCC. Additionally, changes suggestive of an early Bowenoid in situ carcinoma (BISC) were present in the overlying epidermis. Both the BCC and the BISC contained papillomavirus-induced cell changes and prominent basophilic intracytoplasmic bodies. PCR using consensus primers and primers specific for Felis catus papillomavirus types 2 and 3 (FcaPV-2 and -3) was used to amplify papillomaviral DNA. The same papillomaviral DNA sequence was present in the BCC and the BISC. This sequence was most similar to FcaPV-3, but with just 70.5% similarity, was from a novel papillomavirus type. No recurrence or further masses developed.

CONCLUSIONS: This case is unusual due to the presence of a large dermal BCC associated with minimal BISC changes in the overlying epidermis. Additionally, papillomavirus-induced cell changes have not been described previously in a BCC. Furthermore, both the BCC and the BISC contained sequences from a novel papillomavirus type. These observations suggest that the development of some BCCs could be influenced by papillomavirus infection. The novel papillomavirus type detected is the third papillomavirus type to be associated with skin cancer in cats.