Comparison of Subtypes of Penile Squamous Cell Carcinoma From High and Low Incidence Geographical Regions

Abstract

There is a worldwide geographical variation in the incidence of penile squamous cell carcinoma (PSCC); some subtypes are HPV-related (warty, basaloid) while others (keratinizing variants) are not. The aims of this study were to compare the distribution of different histological subtypes of PSCC from regions of low (Paraguay, 144 cases) and high (USA, 157 cases) incidence and to identify and compare tumors with and without warty and/or basaloid morphology. The distribution of subtypes in the Paraguayan and the American series was: usual, 49.3 and 46.5%; verrucous, 8.3 and 7.6%; papillary NOS, 7.6 and 5.7%; warty, 6.9 and 8.3%; basaloid, 4.2 and 7.0%; sarcomatoid, 0.7 and 0.6%; adenosquamous, 3.5 and 0.6%; and mixed, 19.4 and 23.6%, respectively. The distribution of mixed PSCC was: warty-basaloid, 50.0 and 59.5%; usual-verrucous, 21.4 and 21.6%; usual-warty, 14.3 and 8.1%; usual-basaloid, 7.1 and 0.0%; usual-papillary, 3.6 and 5.4%; and others, 3.6 and 5.4%, respectively. In conclusion, we found no geographical difference in the incidence of histological subtypes (p = 0.6501), mixed PSCC (p = 0.5937) or HPV-related tumors (p = 0.2505). Geographical variation may be the result of staging variation at clinical presentation or of pathological diagnosis. The identification of similar histological subtypes in both series validates this classification approach for penile cancer. The tendency for typical SCC to mix with verrucous and papillary carcinomas and of the basaloid to preferentially mix with benign condyloma and condylomatous (warty) carcinomas would support the hypothesis of the existence of an etiologically different dual population of penile tumors.

The variable morphological spectrum of penile basaloid carcinomas: differential diagnosis, prognostic factors and outcome report in 27 cases classified as classic and mixed variants

“…The finding may be an indication of ethnic or cultural (late diagnosis) geographic differences among countries. The differences are more likely restricted to mortality and not to relative frequencies of histological subtypes since in other studies we found no geographical differences in the distribution of histological subtypes of penile SCCs, including the basaloid carcinomas [31,32]. There is a recent study suggesting a higher frequency of HPV-related carcinomas, among them the basaloid tumors, in African patients comparing to patients from other continents with the same tumor subtypes [19].…”

Warty–basaloid carcinoma: clinicopathological features of a distinctive penile neoplasm. Report of 45 cases

“…9,18,19 Other mixed forms of penile squamous cell carcinomas have been reported as part of larger series. 9,17 We are describing a hitherto poorly recognized mixed neoplasm exhibiting warty and basaloid features. Considering their common human papillomavirus-related pathogenesis and the existence of morphological mixed forms, warty and basaloid carcinomas would represent the low-and high-grade ends of a clinicopathological spectrum.…”

“…3,17 Often it is problematic to classify and evaluate the prognostic significance of these mixed variants. Well known is the mixed usual-verrucous (hybrid) carcinoma with its increased risk for nodal metastasis when compared with pure verrucous carcinoma.…”

The Impact of Human Papillomavirus on Cancer Risk in Penile Cancer

“…Considering that the incidence of penile and cervical cancers is high in the same geographical areas, it is reasonable to assume that both types of cancer share the same etiological factors. However, less than half of penile cancers are related to HPV infection (Gross & Pfister, 2004;Rubin et al, 2001) whereas the virus is found in almost all cervical SCCs (Chaux et al, 2010).…”