Using colorimetric in situ hybridisation method for FcaPV-2 to estimate postsurgical prognosis in feline Bowenoid in situ carcinoma.

Background: Feline Bowenoid in situ carcinoma (BISC) is frequently associated with Felis catus papillomavirus-2 (FcaPV-2). Although surgical excision of BISC is expected to be curative, recurrent lesions are reported and it is not known whether it is a consequence of incomplete surgery or residual viral load.

Objectives: To combine colorimetric in situ hybridisation (CISH) and quantitative (q)PCR for the detection of viral DNA, and to correlate the clinical outcome of cats with BISC in which FcaPV-2 DNA is detected at surgical margins.

Animals: Twenty-seven cats with a histopathological diagnosis of BISC.

Materials and methods: Sections including core and margins of the lesions were used for histopathological evaluation, qPCR and CISH. After surgical removal of the lesion, clinical follow-up data were recorded for 6 months.

Results: Six of 12 cases in which all four histological margins were evaluable were used to correlate the infection status at the margins with the follow-up data. Four showed margin positivity, of which half relapsed as expected and half cured; two cases were negative, of which one cured as expected while the other relapsed. Fifteen cases where only three, two or one of the histological margins were evaluable, were considered to adequately correlate the status of infection with the follow-up data if CISH was positive. Follow-up data were available for three with positive margins: one relapsed while the other two were cured.

Conclusions and clinical relevance: Wide clinical surgical margins are always recommended for neoplastic conditions, yet there was no evidence that CISH margin examination would be beneficial in predicting recurrence in this viral-induced lesion.