Detection of human papillomavirus in warty carcinoma of the uterine cervix: comparison of immunohistochemistry, in situ hybridization and in situ polymerase chain reaction methods.

Warty carcinoma of the uterine cervix is a very rare specific variant of invasive squamous cell carcinoma, usually described as a hybrid feature of condyloma with invasive squamous cell carcinoma. Besides having the koilocytes and maturation of squamous epithelium, there is unequivocal stromal invasion. The feathery surface seems to be characteristic of warty carcinoma, differentiating it from condylomata acuminata or verrucous carcinoma. Using in situ polymerase chain reaction (IS-PCR) and in situ hybridization (ISH) as well as an immunohistochemical technique (IHC), we determined the amplification and expression of several human papilloma virus (HPV) types (6, 11, 33, 16 and 18) in nine warty carcinomas of the uterine cervix. We found amplified HPV predominantly in the nuclei of the feathery surface in all cases only when IS-PCR was applied, while it was detected only in five (55.6%) or six cases (66.7%) by conventional IHC or ISH, respectively. We found multiple types in the same lesion in six cases (66.7%) by IS-PCR, in comparison with ISH which detected a lower incidence (22.2%). This finding of coinfection is more consistent with that seen in low-grade squamous intraepithelial lesions (LSILs) of the uterine cervix than in high SIL. It is important to be aware of these distinct lesions in postmenopausal women with their characteristic feathery and thin surface, as well as a hybrid form of exophytic condyloma and stromal invasion, and frequent coinfection of multiple different HPVs as a type of LSILs.