The dual pathogenesis of penile neoplasia: The heterogeneous morphology of human papillomavirus-related tumors

OBJECTIVE: Penile neoplasia, usually of squamous histogenesis, is currently classified into human papillomavirus (HPV)-related or -dependent and non-HPV-related or -independent. There are distinct morphological differences among the two groups. New research studies on penile cancer from Northern countries showed that the presence of HPV is correlated with a better prognosis than virus negative people, while studies in Southern countries had not confirmed, perhaps due to differences in staging or treatment. METHODS: We focused on the description of the HPV-related carcinomas of the penis. The approach was to describe common clinical features followed by the pathological features of each entity or subtype stressing the characteristics for differential diagnosis, HPV genotypes, and prognostic features of the invasive carcinomas. Similar structure was followed for penile intraepithelial neoplasia, except for prognosis because of the scant evidence available. RESULTS: Most of HPV-related lesions can be straightforwardly recognized by routine hematoxylin and eosin stains, but in some cases surrogate p16 immunohistochemical staining or molecular methods such as in situ hybridization or polymerase chain reaction can be utilized. Currently, there are eight tumor invasive variants associated with HPV, as follows: basaloid, warty, warty-basaloid, papillary basaloid, clear cell, medullary, lymphoepithelioma-like, and giant condylomas with malignant transformation. CONCLUSION: This review presents and describes the heterogeneous clinical, morphological, and genotypic features of the HPV-related subtypes of invasive and non-invasive penile neoplasia.