Papillomavirus genotyping on formaldehyde fixed paraffin-embedded tissues in vulvar intraepithelial neoplasia.

PURPOSE: Few studies have described the epidemiology of human papillomavirus (HPV) in vulvar intraepithelial neoplasia (VIN). The aim of this study was to genotype HPV on formalin fixed paraffin-embedded tissues in VIN lesions.

METHODS: A 5-year retrospective study was conducted by including all patients attending the teaching hospital of Nice with a diagnosis of VIN between 1st January 2010 and 31st December 2014. For all patients, HPV genotyping was performed with the PapilloCheck® microarray kit, routinely used on cervical cytology samples, and optimized for formaldehyde fixed paraffin-embedded tissues in VIN.

RESULTS: Forty patients were included in the study: 39 patients had usual VIN and one presented with differentiated VIN. Among the 39 patients with usual VIN, the prevalence of HPV was 90% (35/39). Thirty-two patients had high grade VIN (82%) and seven low grade VIN (18%). In high grade VIN, the most represented HPV types were: HPV 16 (21/32 66%), HPV 56 (3/32 9%) and HPV 33 (2/32 6%). In low grade VIN, the most represented HPV types were: HPV 16 (4/7 57%) and HPV 6 (3/7 43%). Interestingly, 5/39 (13%) of patients diagnosed with usual VIN also had co-existing lichen sclerosus.

CONCLUSIONS: We have optimized a HPV genotyping technique, routinely used on cervical cytology samples, and on paraffin fixed embedded tissue showing VIN. Moreover, we have identified five patients with lichen sclerosus co-existing with usual VIN. This association has rarely been reported and proves that these two entities can coexist.