Possible novel manifestations of papillomaviral skin disease in 4 cats, including sebaceous gland adenoma, viral plaques confined to the digits, and a viral plaque containing novel cytopathic features and felis catus type 8 DNA sequences

Papillomaviruses (PVs) are associated with a variety of skin lesions in cats. Herein, is reported 4 cats with unusual lesions that were associated with PV infection. For each case, the lesions were examined histologically, and p16 CDKN2A protein immunolabeling was performed. Total DNA was extracted from the lesions, and both consensus and specific PCR primers were used to amplify PV DNA. In addition, in situ hybridization (ISH) was used to try to detect PV DNA within 2 of the lesions. Two cats had benign proliferations of sebaceous glands that contained histological changes suggestive of PV infection. Lesions from both cats were found to contain FcaPV5 DNA, although ISH was unable to localize PV DNA within either lesion. Another cat had multiple ulcerated lesions that were confined to the digits. Histology of one of these lesions was consistent with a viral plaque. The plaque contained PV-induced cell changes and FcaPV2 sequences. The fourth cat had a viral plaque that contained FcaPV8 DNA sequences. The epithelial cells within this plaque contained large spherical eosinophilic cytoplasmic bodies that have not been previously described and could therefore be unique to this FcaPV type. The findings from these 4 cats expand the range of lesions associated with FcaPVs in cats and suggest that careful evaluation of epithelial skin lesions for the possibility of an FcaPV cause is warranted. It is important to determine whether lesions are caused by PV infection due to the increased likelihood that multiple lesions will develop in affected cats.