Detection of human papillomavirus type 33 DNA in extragenital Bowen's disease with the polymerase chain reaction

Background: Data on the association of human papillomavirus (HPV) infection with extragenital Bowen's disease are very scarce. Objective: To evaluate the prevalence of HPV infection in extragenital Bowen's disease showing histologically a number of koilocytes in the lesional epidermis, we studied formalin-fixed, paraffin-embedded tissues of 9 such cases. Methods: HPV DNA was studied in such samples by the polymerase chain reaction (PCR) and in situ hybridization. Results: Despite negative results with in situ hybridization, the PCR with HPV type 33 primer detected the presence of virus DNA in 2 our of 9 cases. Conclusion: As far as we know, this is the first report of the detection of HPV type 33 DNA in the lesional skin of extragenital Bowen's disease. The prevalence of HPV infection in extragenital Bowen's disease may be higher than expected, especially in cases histologically showing many koilocytes in the lesional epidermis.