Lichen sclerosus is frequently present in penile squamous cell carcinomas but is not always associated with oncogenic human papillomavirus

Leveraging innovative therapies with an evolving understanding of the molecular pathogenesis of penile squamous cell carcinoma

Penile squamous cell carcinoma is a rare condition that is associated with significant morbidity and mortality in its advanced stages. In today's rapidly evolving field of oncology, physicians and scientists are learning to harness the power of genomics to drive innovative targeted, immunotherapeutic, and multimodal strategies across different cancer types; however, there remains a pressing need for a deeper understanding of the molecular pathways of penile carcinogenesis in order to help direct individualized therapy for patients with this disease. In this article, we will review our current understanding of some of the biologic mechanisms, including virally and nonvirally based pathways, which are thought to drive the development and progression of penile cancer.

[Epidemiology of penile cancer]

BACKGROUND

Penile cancer represents a rarity in daily clinical practice.

OBJECTIVES

The aim is to identify global differences concerning the incidence, social and risk factors.

METHODS

The past and current epidemiologic literature is analyzed concerning incidence rates and risk factors. The latter are discussed concerning their potential with regard to disease prevention.

RESULTS

Globally, incidence rates of penile cancer range from low to nonexistent. Distinct differences are found when comparing industrialized countries with emerging and developing countries. Phimosis seems to be a crucial risk factor in the formation of penile cancer. Additionally, chronic inflammatory diseases of the penis were found to be associated with a higher risk.

CONCLUSIONS

Preventive measures should be considered in relation to the rarity of the disease, especially in the valuation of circumcision during early childhood. Regular clinical examination of the penis is a sensible measure of early detection.

Prevalence of human papillomavirus DNA and p16INK4a in penile cancer and penile intraepithelial neoplasia: a systematic review and meta-analysis

BACKGROUND

Although previous meta-analyses have examined human papillomavirus (HPV) DNA prevalence in penile cancer, none, to our knowledge, have assessed pooled HPV DNA prevalence in penile intraepithelial neoplasia or p16^INK4a percent positivity in penile cancer and penile intraepithelial neoplasia. Therefore, we aimed to examine the prevalence of HPV DNA and p16^INK4a positivity in penile cancer and penile intraepithelial neoplasia worldwide.

METHODS

In this systematic review and meta-analysis, we searched PubMed, Embase, and the Cochrane Library until July 24, 2017, for English-language articles published from Jan 1, 1986, onwards reporting the prevalence of HPV DNA and p16^INK4a positivity, either alone or in combination, in at least five cases of penile cancer or penile intraepithelial neoplasia. Only studies that used PCR or hybrid capture for the detection of HPV DNA and immunohistochemical staining or methylation for the detection of p16^INK4a were included. Data were extracted and subsequently crosschecked, and inconsistencies were discussed to reach consensus. Using random-effects models, we estimated the pooled prevalence and 95% CI of HPV DNA and p16^INK4a positivity in penile cancer and penile intraepithelial neoplasia, stratifying by histological subtype and HPV DNA or p16^INK4a detection method. Type-specific prevalence of HPV6, HPV11, HPV16, HPV18, HPV31, HPV33, and HPV45 in penile cancer was estimated.

FINDINGS

Our searches identified 1836 non-duplicate records, of which 73 relevant papers (71 studies) were found to be eligible. The pooled HPV DNA prevalence in penile cancer (52 studies; n=4199) was 50·8% (95% CI 44·8-56·7; I²=92·6%, p_{heterogeneity}<0·0001). A high pooled HPV DNA prevalence was seen in basaloid squamous cell carcinomas (84·0%, 95% CI 71·0-93·6; I²=48·0%, p_{heterogeneity}=0·0197) and in warty-basaloid carcinoma (75·7%, 70·1-81·0; I²=0%, p_{heterogeneity}=0·52). The predominant oncogenic HPV type in penile cancer was HPV16 (68·3%, 95% CI 58·9-77·1), followed by HPV6 (8·1%, 4·0-13·7) and HPV18 (6·9%, 2·9-12·4). The pooled HPV DNA prevalence in penile intraepithelial neoplasia (19 studies; n=445) was 79·8% (95% CI 69·3-88·6; I²=83·2%, p_{heterogeneity}<0·0001). The pooled p16^INK4a percent positivity in penile cancer (24 studies; n=2295) was 41·6% (95% CI 36·2-47·0; I²=80·6%, p_{heterogeneity}<0·0001), with a high pooled p16^INK4a percent positivity in HPV-related squamous cell carcinoma (85·8%, 95% CI 72·1-95·4; I²=56·4%, p_{heterogeneity}=0·0011) as compared with non-HPV-related squamous cell carcinoma (17·1%, 7·9-29·1; I²=78·3%, p_{heterogeneity}<0·0001). Moreover, among HPV-positive cases of penile cancer, the p16^INK4a percent positivity was 79·6% (95% CI 65·7-90·7; I²=89·9%, p_{heterogeneity}<0·0001), compared with 18·5% (9·6-29·6; I²=89·3%, p_{heterogeneity}<0·0001) in HPV-negative penile cancers. The pooled p16^INK4a percent positivity in penile intraepithelial neoplasia (six studies; n=167) was 49·5% (95% CI 18·6-80·7).

INTERPRETATION

A large proportion of penile cancers and penile intraepithelial neoplasias are associated with infection with HPV DNA (predominantly HPV16), emphasising the possible benefits of HPV vaccination in men and boys.

FUNDING

None.

Balanitis xerotica obliterans: a review of diagnosis and management

Balanitis xerotica obliterans (BXO), or penile lichen sclerosus, is a progressive sclerosing inflammatory dermatosis of the glans penis and foreskin. It is associated with significant morbidity and may result in impaired urinary and sexual function. It was initially described by Stuhmer in 1928, named after its pathological features, and is considered the male equivalent of vulvar lichen sclerosis (LS).^3,40 The etiology of BXO is uncertain; however, autoimmune disease, local trauma, and genetic and infective causes have been proposed. BXO occurs most commonly on the prepuce and glans penis. It is considered to have premalignant potential to transform into squamous neoplasia. This postulation rests on retrospective studies and parallels drawn with vulvar LS and squamous cell carcinoma (SCC) development. Histologically, BXO and vulvar LS are considered the same disease.⁴¹ There is a paucity of evidence-based guidelines to assist with appropriate follow-up for patients with BXO.

New cancer cases in France in 2015 attributable to infectious agents: a systematic review and meta-analysis

To provide an assessment of the burden of cancer in France in 2015 attributable to infectious agents. A systematic literature review in French representative cancer cases series was undertaken of the prevalence of infectious agents with the major associated cancer types. PubMed was searched for original studies published up to September 2016; random-effects meta-analyses were performed. Cancer incidence data were obtained from the French Cancer Registries Network, thereby allowing the calculation of national incidence estimates. The number of new cancer cases attributable to infectious agents was calculated using population-attributable fractions according to published methods. Of the 352,000 new cancer cases in France in 2015, 14,336 (4.1% of all new cancer cases) were attributable to infectious agents. The largest contributors were human papillomavirus (HPV) and Helicobacter pylori, responsible for 6333 and 4406 new cancer cases (1.8 and 1.3% of all new cancer cases) respectively. Infectious agents caused a non-negligible number of new cancer cases in France in 2015. Most of these cancers were preventable. The expansion of vaccination (i.e., for hepatitis B virus and HPV) and screen-and-treat programs (for HPV and hepatitis C virus, and possibly for H. pylori) could greatly reduce this cancer burden.

The presence of human papillomavirus and Epstein-Barr virus in male Chinese lichen sclerosus patients: a single center study

This study aimed to investigate the presence of human papillomavirus and Epstein-Barr virus in male lichen sclerosus patients. We extracted DNA from formalin-fixed paraffin-embedded foreskin tissue blocks of 47 male LS patients and 30 healthy men and performed real-time PCR test to detect HPV and EBV. None of the 47 LS patients and 30 healthy men had detectable HPV infection. EBV was detected in 18 LS patients (38.3%) and four healthy men (13.3%), the difference is significant (P < 0.05). Tissue blocks with significant inflammatory reaction tend to have higher EBV load. HPV has no significant relationship with LS. Male LS patients have higher EBV infection rate, but the role of EBV in the pathogenesis of LS needs further investigate.

Review of in situ and invasive penile squamous cell carcinoma and associated non-neoplastic dermatological conditions

Penile carcinoma is a rare genitourinary malignancy in North America and Europe with highest rates recorded in South America, Africa and Asia. Recent classifications have refined the terminology used in classifying intraepithelial/in situ lesions and additionally newer entities have been recognised in the invasive category. While increasing recognition of a bimodal pathway of penile carcinogenesis has facilitated understanding and classification of these tumours, handling and subtyping of penile malignancies presents a challenge to the reporting pathologist, in part due to their rarity. This article reviews the terminology and classification of in situ and invasive carcinomas and their relationship to human papilloma virus status. In addition, associated non-neoplastic dermatological conditions of relevance and appropriate ancillary investigations will be addressed.

Differential gene hypermethylation in genital lichen sclerosus and cancer: a comparative study

AIMS

Lichen sclerosus (LS) is a chronic inflammatory disease of the genital skin of unknown aetiology. The role of LS in penile squamous cell carcinogenesis is not well characterized. HPV has been implicated in both, as have epigenetic changes. The presence of HPV and hypermethylation of the MGMT, p16, RASSF1, RASSF2, TSLC1 and TSP1 genes were studied in penile LS; MGMT, RASSF2 and TSLC1 hypermethylation in penile cancer and TSLC1 hypermethylation in vulvar LS and cancer extends previous results reported by our group.

METHODS AND RESULTS

Thirty-seven HPV genotypes and hypermethylation were evaluated by PCR/reverse-line-blot and methylation-specific PCR respectively, in 27 preputial LS, 24 penile SCC, 30 vulvar SCC, 21 vulvar LS and 22 normal skin cases. HPV66 was present in 3.7% of penile LS cases, and p16 and RASSF2 hypermethylation were more frequent in penile cancer than in penile LS. p16, RASSF1, RASSF2 and TSP1 hypermethylation were similar in penile and vulvar LS.

CONCLUSIONS

Gene hypermethylation is a common event in penile LS, and occurs approximately as frequently as in vulvar LS. Certain genes can be hypermethylated as an early or late event in LS or cancer, respectively. This suggests a possible sequential role for these alterations in the transition from benign to malignant lesions.

Primary prevention and vaccination for penile cancer

The outcome of penile cancer is proportional to the stage at presentation. Strategies aimed at primary prevention would have a clear advantage, both for the individual and in terms of health economics. A number of preventative measures could be employed, including circumcision, smoking cessation, education on hygiene and human papillomavirus (HPV) prevention. There is a high prevalence of HPV infection associated with penile cancer worldwide. The recent development of HPV vaccines has facilitated interest in their use for the prevention of penile cancer. In this article we review the literature surrounding penile cancer prevention and HPV vaccination in men.

Diagnosis and treatment of lichen sclerosus: an update

Lichen sclerosus (LS) is a chronic, inflammatory, mucocutaneous disorder of genital and extragenital skin. LS is a debilitating disease, causing itch, pain, dysuria and restriction of micturition, dyspareunia, and significant sexual dysfunction in women and men. Many findings obtained in recent years point more and more towards an autoimmune-induced disease in genetically predisposed patients and further away from an important impact of hormonal factors. Preceding infections may play a provocative part. The role for Borrelia is still controversial. Trauma and an occlusive moist environment may act as precipitating factors. Potent and ultrapotent topical corticosteroids still head the therapeutic armamentarium. Topical calcineurin inhibitors are discussed as alternatives in the treatment of LS in patients who have failed therapy with ultrapotent corticosteroids, or who have a contraindication for the use of corticosteroids. Topical and systemic retinoids may be useful in selected cases. Phototherapy for extragenital LS and photodynamic therapy for genital LS may be therapeutic options in rare cases refractory to the already mentioned treatment. Surgery is restricted to scarring processes leading to functional impairment. In men, circumcision is effective in the majority of cases, but recurrences are well described. Anogenital LS is associated with an increased risk for squamous cell carcinoma of the vulva or penis. This review updates the epidemiology, clinical presentation, histopathology, pathogenesis, and management of LS of the female and male genitals and extragenital LS in adults and children.

Genital lichen sclerosus/balanitis xerotica obliterans in men with penile carcinoma: a critical analysis

WHAT'S KNOWN ON THE SUBJECT? AND WHAT DOES THE STUDY ADD?: The European Association of Urology guidelines identify lichen sclerosus (LS) as a strong risk factor for penile squamous cell carcinoma (pSCC). However, this statement is based on the findings of case-control studies (Level of Evidence 2a) and a direct causal relationship between LS/balanitis xerotica obliterans (BXO) and pSCC remains to be established. Firm guidelines with respect to the appropriate follow-up policy for LS/BXO are lacking, whereas the impact of synchronous LS/BXO on the prognosis of pSCC remains to be determined. The presence of histologically-confirmed synchronous LS/BXO in patients diagnosed with pSCC is relatively high, although it is not associated with an increased risk of adverse histopathological features. LS/BXO can develop in extragenital skin grafts used for reconstruction after organ-sparing surgery for pSCC.

OBJECTIVES

To determine the rate of lichen sclerosus/balanitis xerotica obliterans (LS/BXO) in patients with penile squamous cell carcinoma (pSCC) and establish whether the presence of LS/BXO is associated with adverse histopathological features of pSCC. To report the phenomenon of LS involving non-genital skin grafts in patients who underwent organ-sparing surgery and split-skin graft (SSG) reconstruction

PATIENTS AND METHODS

Between January 2002 and January 2010, 223 men underwent surgical treatment for pSCC. A group of 52 patients with histologically-confirmed synchronous LS was identified (group A; overall rate of LS/BXO = 23.3%) and compared with a group of patients without synchronous LS (group B; n = 171; 76.7%). A subgroup of patients who underwent surgical excision and SSG reconstruction was also identified The histology reports of graft biopsies obtained during follow-up were reviewed and the rate of LS involving the graft was also recorded.

RESULTS

Mean (range) age at diagnosis was 60.9 (34-81) years and 60.7 (28-89) years for groups A and B, respectively (P = 0.958). The mean (range) duration of follow-up was 38.3 (4-92) months for group A and 45.5 (4-107) months for group B (P = 0.162) No statistically significant differences were noted between groups A and B in terms of tumour grade (P = 0.091), stage (P = 0.697), presence of lymphovascular invasion (P = 0.333), histological subtype (P = 0.107), associated carcinoma in situ (P = 0.246) or nodal status at initial diagnosis (P = 0.555). In the subgroup of 188 patients who underwent SSG reconstruction, 41 (21.8%) patients had histologically-confirmed synchronous LS; in this subgroup, 26 (13.8%) patients underwent graft biopsy during follow-up. Genital LS involving the graft was identified in seven specimens, although none of these seven cases had associated recurrent pSCC.

CONCLUSIONS

The presence of histologically-confirmed synchronous LS in patients with pSCC is relatively high but is not associated with increased rates of adverse histopathological features, including carcinoma in situ. LS can develop in extragenital skin grafts, although its association with the long-term risk for recurrent pSCC is not apparent in the present study.

Male genital premalignant dermatoses

The spectrum of conditions affecting the penile skin is varied and ranges from simple, benign dermatoses to premalignant and malignant conditions. Recently, improved understanding of the aetiology and natural history of these conditions has shaped new treatment paradigms and a functional knowledge of dermatology, urology and genitourinary medicine is required to successfully diagnose and treat these men. In this article, we explore the common precancerous states that can lead to penile carcinoma and review the recent advances with regards to the molecular basis for these dermatoses and the treatments that may be most effective for these men.

Lichen sclerosus and squamous cell carcinoma

Lichen sclerosus is a chronic inflammatory disease that can progress to malignancy. The literature indicates an association with anogenital squamous cell carcinoma and verrucous carcinoma. Two pathogenic pathways, differentiated vulvar and penile intraepithelial neoplasias, which have recently been described in relation to squamous cell carcinoma, are both highly associated with genital lichen sclerosus independently of human papilloma virus (HPV) infection. Furthermore, tumor-promoting molecular changes unrelated to HPV infection have been demonstrated and may explain the malignant potential of lichen sclerosus. The possible relationship between HPV and genital lichen sclerosus currently remains open to discussion, and the prognostic importance of the overlapping of these 2 diseases is still unclear. This review considers the relationship between lichen sclerosus and squamous cell and verrucous carcinomas, the possible oncogenic mechanisms involved, and their possible association with HPV infection.

[Lichen sclerosus and squamous cell carcinoma]

Lichen sclerosus is a chronic inflammatory disease that can progress to malignancy. The literature indicates an association with anogenital squamous cell carcinoma and verrucous carcinoma. Two pathogenic pathways, differentiated vulvar and penile intraepithelial neoplasias, which have recently been described in relation to squamous cell carcinoma, are both highly associated with genital lichen sclerosus independently of human papilloma virus (HPV) infection. Furthermore, tumor-promoting molecular changes unrelated to HPV infection have been demonstrated and may explain the malignant potential of lichen sclerosus. The possible relationship between HPV and genital lichen sclerosus currently remains open to discussion, and the prognostic importance of the overlapping of these 2 diseases is still unclear. This review considers the relationship between lichen sclerosus and squamous cell and verrucous carcinomas, the possible oncogenic mechanisms involved, and their possible association with HPV infection.

Gene expression profiling in male genital lichen sclerosus

Male genital lichen sclerosus (MGLSc) has a bimodal distribution in boys and men. It is associated with squamous cell carcinoma (SCC). The pathogenesis of MGLSc is unknown. HPV and autoimmune mechanisms have been mooted. Anti extracellular matrix protein (ECM)1 antibodies have been identified in women with GLSc. The gene expression pattern of LSc is unknown. Using DNA microarrays we studied differences in gene expression in healthy and diseased prepuces obtained at circumcision in adult males with MGLSc (n = 4), paediatric LSc (n = 2) and normal healthy paediatric foreskin (n = 4). In adult samples 51 genes with significantly increased expression and 87 genes with significantly reduced expression were identified; paediatric samples revealed 190 genes with significantly increased expression and 148 genes with significantly reduced expression. Concordance of expression profiles between adult and paediatric samples indicates the same disease process. Functional analysis revealed increased expression in the adult and child MGSLc samples in the immune response/cellular defence gene ontology (GO) category and reduced expression in other categories including genes related to squamous cancer. No specific HPV, autoimmune or squamous carcinogenesis-associated gene expression patterns were found. ECM1 and CABLES1 expression were significantly reduced in paediatric and adult samples respectively.

Clinical parameters in male genital lichen sclerosus: a case series of 329 patients

BACKGROUND

  The dermatological aspects of male genital lichen sclerosus (MGLSc) have not received much prominence in the literature. Sexual morbidity appears under-appreciated, the role of histology is unclear, the relative places of topical medical treatment and circumcision are not established, the prognosis for sexual function, urinary function and penis cancer is uncertain and the pathogenesis has not been specifically studied although autoimmunity (as in women) and HPV infection have been mooted.

OBJECTIVE

  To illuminate the above by analysing the clinical parameters of a large series of patients with MGLSc.

METHODS

  A total of 329 patients with a clinical diagnosis of MGLSc were identified retrospectively from a dermatology-centred multidisciplinary setting. Their clinical and histopathological features and outcomes have been abstracted from the records and analysed by simple descriptive statistics.

RESULTS

  The collation and analysis of clinical data derived from the largest series of men with MGLSc ever studied from a dermatological perspective has been achieved. These data allow the conclusions below to be drawn.

CONCLUSIONS

  MGLSc is unequivocally a disease of the uncircumcised male; the adult peak is late in the fourth decade; dyspareunia is a common presenting complaint; non-specific histology requires careful interpretation; most men are either cured by topical treatment with ultrapotent steroid (50-60%) or by circumcision (>75%); effective and definitive management appears to abrogate the risk of developing penile squamous cell carcinoma; urinary contact is implicated in the pathogenesis of MGLSc; HPV infection and autoimmunity seem unimportant.

The Strong Protective Effect of Circumcision against Cancer of the Penis

Male circumcision protects against cancer of the penis, the invasive form of which is a devastating disease confined almost exclusively to uncircumcised men. Major etiological factors are phimosis, balanitis, and high-risk types of human papillomavirus (HPV), which are more prevalent in the glans penis and coronal sulcus covered by the foreskin, as well as on the penile shaft, of uncircumcised men. Circumcised men clear HPV infections more quickly. Phimosis (a constricted foreskin opening impeding the passage of urine) is confined to uncircumcised men, in whom balanitis (affecting 10%) is more common than in circumcised men. Each is strongly associated with risk of penile cancer. These findings have led to calls for promotion of male circumcision, especially in infancy, to help reduce the global burden of penile cancer. Even more relevant globally is protection from cervical cancer, which is 10-times more common, being much higher in women with uncircumcised male partners. Male circumcision also provides indirect protection against various other infections in women, along with direct protection for men from a number of genital tract infections, including HIV. Given that adverse consequences of medical male circumcision, especially when performed in infancy, are rare, this simple prophylactic procedure should be promoted.

Penile cancer--prevention and premalignant conditions

OBJECTIVES

Relatively little evidence is available in the published studies on the prevention of penile cancer and premalignant conditions of the penis. The present review examined the current evidence available in preventing penile cancer and pathologic subtypes of premalignant conditions and their treatment. The recommendations made in the present review formulate the basis of the recent 2009 International Consultation on Urologic Disease Consensus Publishing Group.

METHODS

The association of human papillomavirus subtypes and penile cancer is well-established, although the etiology, natural history, and treatment of premalignant lesions have mainly been reported in retrospective case series with short-term follow-up. The exact pathologic role of chronic inflammatory conditions, such as balanitis xerotica obliterans in the etiology of penile cancer remains largely unknown.

RESULTS

Some of the potential strategies for the prevention of penile cancer could include circumcision, reducing the risk of transmission of penile human papillomavirus infection with male vaccination, early treatment of phimosis, smoking cessation, and hygienic measures. Implementing some of these measures would require extensive cost/benefit analysis, with significant changes in the global health policy.

CONCLUSIONS

Owing to the current levels of evidence from published studies, firm guidelines cannot be formulated for the treatment of premalignant conditions, although preventative measures, such as reducing human papillomavirus transmission, could become strategic health targets.

Human papillomavirus prevalence and type distribution in penile carcinoma

BACKGROUND

Penile carcinoma is an uncommon and potentially mutilating disease with a heterogeneous aetiology. Several risk factors have been established for its development. Human papillomavirus (HPV) infection seems to play an important role in the development of a subset of these carcinomas and its presence is thought to be related to the histological type. HPV prevalence in penile tumours is reported to be associated to a variety of morphological changes. Its determination will provide a better estimate for HPV related cancer burden and its preventable fraction.

METHODS

A systematic and comprehensive literature review of the major penile cancer studies published from 1986 until June 2008 evaluating the HPV prevalence among the different histological types was carried out.

RESULTS

31 studies including 1466 penile carcinomas were reviewed. Global HPV prevalence was 46.9%. Relative contribution was: HPV-16 (60.23%), HPV-18 (13.35%), HPV-6/11 (8.13%), HPV-31 (1.16%), HPV-45 (1.16%), HPV-33 (0.97%), HPV-52 (0.58%), other types (2.47%). Assessment of multiple infections contribution is limited due to study design. Basaloid and warty squamous cell carcinomas were the most frequent HPV-related histological types, but keratinising and non-keratinising subtypes also showed prevalence rates of around 50%.

CONCLUSIONS

About half of the penile tumours were associated with HPV 16-18 with little presence of other genotypes. Research on the mechanisms behind penile carcinogenesis is warranted. Available HPV vaccines are likely to be effective in penile tumours.

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

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.

Benign Diseases and Neoplasms of the Penis

This article provides comprehensive review of benign diseases and neoplastic conditions of the penis. It describes and provides representative images of clinical, key pathologic features and ancillary techniques to aid in differential diagnoses. It examines these diseases from the epidemiologic standpoint, looks at environmental and genetic factors, and outlines the new histologic entities for penile neoplasms with distinct outcomes and clinical behavior that have been proposed in recent years.

Systematic review of human papillomavirus prevalence in invasive penile cancer

OBJECTIVE

Type-specific prevalence data of human papillomavirus (HPV) DNA in penile carcinoma are needed to determine the potential impact of HPV prophylactic vaccines, assuming demonstrated efficacy in men.

METHODS

A review was conducted using search terms including HPV and penile cancer. Studies using polymerase chain reaction (PCR) assays for HPV DNA detection in invasive penile carcinoma were included.

RESULTS

A total of 1,266 squamous cell carcinoma (SCC) cases contributed data from 30 studies. The number of SCC was similar in Europe (28.2%), North America (27.6%), South America (23.9%) and Asia (20.4%). All SCC were histologically confirmed with biopsies for DNA detection. Most commonly used PCR primers were type-specific (35.2%), and combination PCR (18.2%). HPV prevalence was 47.9%, ranging from 22.4% in verrucous SCC to 66.3% for the basaloid/warty subtypes. HPV16 (30.8%), HPV6 (6.7%) and HPV18 (6.6%) were the most prevalent types. HPV16 and/or HPV 18 prevalence was 36.7%.

CONCLUSIONS

HPV DNA was detected in half of SCC, with HPV16 being the most common type. If proven efficacious in men, prophylactic vaccines targeting carcinogenic types HPV16 and 18 could potentially reduce approximately one-third of incident SCC.

Human papillomavirus-associated increase in p16INK4A expression in penile lichen sclerosus and squamous cell carcinoma

Background

Human papillomaviruses (HPVs) are sexually transmitted human carcinogens that may play a role in the oncogenesis of penile cancer.

Objectives

To investigate the role of HPV infection and expression of the tumour suppressor protein p16^INK4A in the pathogenesis of penile cancer.

Methods

By means of polymerase chain reaction amplification and reverse hybridization line probe assay to detect HPV infection, and immunohistochemical staining for p16^INK4A and Ki67, we analysed 26 penile squamous cell carcinomas (SCCs) and 20 independent penile lichen sclerosus (LS) lesions from 46 patients.

Results

HPV DNA was found in 54% of penile SCCs and 33% of penile LS cases in single and multiple infections. High-risk HPV 16 was the predominant HPV type detected. No relationship between Ki67 expression and HPV infection was observed. Strong immunostaining for p16^INK4A correlated with HPV 16/18 infection in both penile LS and penile SCC. In our penile SCC series the cancer margins were also associated with penile LS in 13 of 26 lesions, and HPV was detected in seven of the 13 SCC cases associated with LS and in six of the 11 SCC lesions not involving LS.

Conclusions

Our study shows a high prevalence of HPV 16 and p16^INK4A expression in penile lesions, consistent with an active role for HPV in interfering with the retinoblastoma pathway. High-risk HPV infection could be involved in the tumorigenic process in 50% of penile cancers, and the use of prophylactic HPV vaccines has the potential to prevent these cancers.

Balanitis Xerotica Obliterans

Balanitis xerotica obliterans (BXO), first described by Stuhmer in 1928, is a chronic, progressive, atrophic, sclerosing process involving prepuce, glans and urethra. Its aetiology is unknown.

After a short terminological excursus and a review of the aetiological hypothesis, we have focused on BXO in daily urological practice.

We are here describing the clinical presentation and its differential diagnosis with premalignant and malignant lesions of the penis. We tried to define the relationship between BXO and squamous cell carcinoma of the penis. Particular attention was then cast on urethral stenosis.

Finally, we focused on the treatment of BXO: corticosteroid local therapy as first line treatment or as adjuvant therapy after circumcision, surgical therapy including circumcision, laser therapy of the glans lesions, meatoplasty in the stenosis of the anterior urethra. We also stressed the need for histological examination of the preputial specimen for a correct follow-up and for medicolegal reasons.

Association of penile lichen sclerosus and oncogenic human papillomavirus infection

BACKGROUND

Data on the prevalence of human papillomavirus (HPV) infection in patients with penile lichen sclerosus (LS) are scant and controversial.

AIM

To investigate the prevalence of HPV infections in patients with penile LS.

METHODS

HPV infection was assessed by polymerase chain reaction (PCR) in paraffin-embedded penile biopsies obtained from the glans or inner foreskin of 46 adult patients with penile LS, and in brush cytology smears of penile healthy mucosa from an equal number of randomly selected control males matched for age. Statistical evaluation was performed using conditional logistic regression analysis.

RESULTS

PCR disclosed the presence of HPV infection in 17.4% of LS patients (HPV 16, six cases; HPV 18, one case; HPV 45, one case). Amongst the controls, HPV infection occurred in 8.7% of patients (HPV 16, two cases; HPV 53, one case; HPV 70, one case). Statistical regression analysis confirmed that the rate of HPV infection was higher amongst patients with genital LS than amongst healthy controls [odds ratio (OR), 2.55; 95% confidence interval (CI), 0.73-8.89].

CONCLUSIONS

Infection with oncogenic "high-risk" HPV types in patients with genital LS may enhance the risk of penile cancer arising on LS.

Penile Carcinoma in Patients With Genital Lichen Sclerosus: A Multicenter Survey

PURPOSE

In this observational descriptive study we reviewed the histology and the clinical records of 130 patients with LS involving the male genitalia to determine the presence of premalignant or malignant lesions.

MATERIALS AND METHODS

A total of 130 male patients (from 1991 to 2001) with genital LS were treated at our centers. Mean patient age at diagnosis was 42.5 years. In all patients with a clinical diagnosis of LS, the histology was reexamined to look for evidence of LS, applying strict histological criteria. All cases of histologically proven epithelial malignancy, namely SCC, VC and EQ, were reviewed to confirm the presence of neoplastic changes and ascertain the degree of SCC differentiation.

RESULTS

Of 130 men 11 (8.4%) with genital LS showed premalignant or malignant histopathological features including 7 (64%) with SCC, 2 (18%) with VC, 1 (9%) with EQ and 1 (9%) with SCC associated with VC. In 6 of 11 patients (55%) the histological study showed the presence of epithelial dysplasia.

CONCLUSIONS

Survival of patients with penile carcinoma depends on early diagnosis and treatment, and all patients with genital LS should be observed closely to detect the development of neoplastic or preneoplastic lesions as early as possible.

Penile cancer

Penile cancer, while relatively rare in the western world, remains a disease with severe morbidity and mortality, not to mention significant psychological ramifications. Furthermore, the disease is observed with dramatically increased incidence in other parts of the world. A review of the literature has shown that the overwhelming majority of penile cancers are in situ or invasive squamous cell carcinomas, including a well-differentiated variant, verrucous carcinoma. Important predisposing factors are lack of circumcision, human papillomavirus infections, and penile lichen sclerosus, although other factors have occasionally been reported as well. Prevention, careful monitoring of patients at risk, and early diagnosis are essential to reduce the incidence of penile carcinoma and to provide a definitive cure. Public health measures, such as prophylactic use of circumcision, have proved successful but are controversial. Also, no standard therapeutic guidelines as to the best treatment strategy according to different stages, including efficacy of conservative nonsurgical modalities and indications for lymph nodal dissection, are available so far. It is common opinion that penile cancer is an emerging problem that deserves further investigations, and physicians, especially dermatologists, should be aware of this issue.

LEARNING OBJECTIVE

At the completion of this learning activity, participants should be familiar with penile carcinoma, its risk factors, its clinical and histologic presentation, and the treatments currently available for its management.