HPV prevalence in anal warts tested with the MY09/MY11 SHARP Signal system.

Anal warts are, from an aetiological point of view, a diverse category of lesions including condylomata acuminata, fibroepithelial polyps and seborrhoeic keratosis. Human papillomavirus induced anal warts, in contrast to other types of warts, are contagious and not infrequently sexually transmitted, they therefore need to be accurately identified. A total of 24 anal warts were randomly collected and the histopathological diagnoses based on microscopy, alone or in combination with a sensitive PCR-based human papillomavirus test, were compared using the SHARP Signal system for detection. Three lesions were identified as condyloma acuminatum by morphology alone due to the obvious presence of koiloytotic atypia; 11 warts without koilocytes were identified only after a positive test for anogenital human papillomavirus. One additional lesion contained human papillomavirus DNA of cutaneous type and 9 papillomas were human papillomavirus-negative and tentatively diagnosed as fibroepithelial polyps or seborrhoeic keratosis. All 14 condylomas contained human papillomavirus of low-risk type. Of these, 12 warts showed a positive human papillomavirus reaction with in situ hybridization. Morphology alone cannot reveal the true nature of most anal papillomas, even when koilocytotic atypia is considered as a diagnostic hallmark. An optimal diagnosis of anal warts requires a sensitive PCR-based human papillomavirus DNA test. A test for identification of cutaneous human papillomavirus DNA is also worthwhile.