Penile carcinogenesis in a low-incidence area: a clinicopathologic and molecular analysis of 115 invasive carcinomas with special emphasis on chronic inflammatory skin diseases.

BACKGROUND: Human papillomavirus (HPV) infections account worldwide for 50% of penile cancers. The role of lichen sclerosus and lichen planus in penile carcinogenesis needs further investigation.

MATERIALS AND METHODS: Archival formalin-fixed high-grade penile intraepithelial neoplasias, differentiated penile intraepithelial neoplasias, and invasive carcinomas from a single pathology institution in a low-incidence area for penile cancer were analyzed for 28 HPV low-risk and HPV high-risk genotypes, p16 overexpression, presence of peritumoral lichen sclerosus, lichen planus, precursor lesions, and monoclonal rearrangement of the T-cell receptor γ locus.

RESULTS: A total of 29 penile intraepithelial neoplasias (100%) and 69 of 115 (60%) invasive cancers contained HPV high-risk genotypes with a single HPV high-risk genotype (80% HPV16, 6% HPV33, 2% HPV45 and HPV18, 1% HPV73). Multiple HPV high-risk genotypes were identified in 4% with and in 5% without HPV16/18. p16 overexpression correlated in all but 1 case of HPV high-risk 45 cancer. No p16 overexpression and HPV genotype was found in 6 differentiated penile intraepithelial neoplasias and 46 of 115 (40%) invasive cancers, 30% of which were pT2/pT3 cancers. For 35 cancers, peritumoral tissue was available for analysis. Advanced lichen sclerosus was identified in 26, lichen planus in 9, and differentiated penile intraepithelial neoplasia in 18 carcinomas. Dense T-cell-dominant lymphocytic infiltrates were identified in 22 of 46 carcinomas and in 3 of 6 differentiated penile intraepithelial neoplasias, with 6 of 13 analyzed carcinomas/penile intraepithelial neoplasias showing a monoclonal rearrangement of the T-cell receptor γ locus.

CONCLUSIONS: The prevalence of HPV high-risk in penile cancers from a low-incidence area was slightly higher than the global distribution. HPV-negative carcinomas were associated with advanced lichen sclerosus and lichen planus, differentiated penile intraepithelial neoplasia, and accumulation of T lymphocytes with monoclonal rearrangement of the T-cell receptor γ locus.