Penile intraepithelial neoplasia: Distribution of subtypes, HPV genotypes and p16INK4a in 84 international cases.

There are few pathologic or molecular studies of penile precancerous lesions, and the majority refers to lesions associated with invasive carcinomas. Penile Intraepithelial Neoplasia (PeIN) is classified in two morphologically and distinctive molecular groups, non-HPV and HPV-related with special subtypes. The primary purpose of this international series was to classify PeIN morphologically, detect HPV genotypes and determine their distribution according to PeIN subtypes. A secondary aim was to evaluate the p16INK4a immunostaining as a possible HPV surrogate for high-risk HPV infection in penile precancerous lesions. Samples consisted of 84 PeIN cases, part of a retrospective cross-sectional analysis of 1095 penile carcinomas designed to estimate the HPV DNA prevalence in penile cancers using PCR and p16INK4a immunostaining. Penile Intraepithelial Neoplasia (PeIN) was classified in HPV-related (basaloid, warty-basaloid, warty, hybrid, and mixed subtypes) and non-HPV-related (differentiated), the former being the most frequent. PeIN subtypes were differentiated (non-HPV-related) and basaloid, warty-basaloid, warty, hybrid and mixed (HPV-related). Basaloid PeIN was the most commonly diagnosed subtype, and HPV16 was the most frequent HPV genotype detected. Warty-basaloid and warty PeIN showed a more heterogeneous genotypic composition. Most HPV genotypes were high-risk but low-risk HPV genotypes were also present in a few cases (4%). A single HPV genotype was detected in 82% of HPV positive cases. In contrast, multiple genotypes were detected in the remaining 18% of cases. The findings in this study support the paradigm that penile in situ neoplasia, like its invasive counterparts, is HPV dependent or independent and has distinctive morphological subtypes readily identified in routine practice. Considering that HPV16 is clearly the predominant type, and that the three available vaccines have HPV16, all of them will be suitable for vaccination programs; the price of the vaccines will be probably the main determinant to choose the vaccine.

Comparison of Human Papillomavirus Genotypes in Penile Intraepithelial Neoplasia and Associated Lesions: LCM-PCR Study of 87 Lesions in 8 Patients.

Penile intraepithelial neoplasia (PeIN) is currently classified in human papillomavirus (HPV)- and non-HPV-related subtypes with variable HPV genotypes. PeINs are frequently associated with other intraepithelial lesions in the same specimen. The aim of this study was to detect and compare HPV genotypes in PeINs and associated lesions using high-precision laser capture microdissection-polymerase chain reaction and p16INK4a immunostaining. We evaluated resected penile specimens from 8 patients and identified 33 PeINs and 54 associated lesions. The most common subtype was warty PeIN, followed by warty-basaloid and basaloid PeIN. Associated lesions were classical condylomas (17 cases), atypical classical condylomas (2 cases), flat condylomas (9 cases), atypical flat condylomas (6 cases), flat lesions with mild atypia (12 cases), and squamous hyperplasia (8 cases). After a comparison, identical HPV genotypes were found in PeIN and associated lesions in the majority of the patients (7 of 8 patients). HPV16 was the most common genotype present in both PeIN and corresponding associated lesion (50% of the patients). Nonspecific flat lesions with mild atypia, classical condylomas, and atypical condylomas were the type of associated lesions most commonly related to HPV16. Other high-risk HPV genotypes present in PeIN and associated nonspecific flat lesion with mild atypia were HPV35 and HPV39. In this study of HPV in the microenvironment of penile precancerous lesions, we identified identical high-risk HPV genotypes in PeIN and classical, flat, or atypical condylomas and, specially, in nonspecific flat lesions with mild atypia. It is possible that some of these lesions represent hitherto unrecognized precancerous lesions.