A clinical, histopathologic, and molecular biologic investigation of vulvar intraepithelial neoplasia

Current Topics in Pathology of Gynecologic Tumors

Over the last decade, the application of new technologieslargely immunohistochemistry and molecular genetics to the study of gynecologic tumors has provided new insights into their pathogenesis. Attempts to integrate the results of these investigations into the conventional clinicopathologic features of the tumors have been made. In this review, which does not intend to be comprehensive, several selected topics dealing with the pathogenesis of gynecologic neoplasms are briefly presented.

Association of human papillomavirus with vulvar and vaginal intraepithelial disease: opportunities for prevention

While the majority of studies regarding the health benefits from human papillomavirus (HPV) vaccination have focused on cervical neoplasia and cancer, few have investigated how the epidemiology of vaginal and vulvar disease may be affected. To better understand how occurrence rates for vaginal and vulvar neoplasias and carcinomas may change in the future, we must have an understanding of the overall disease prevalence within a given population, the efficacy of vaccination and the proportion of cases attributable to HPV types administered in the vaccine. In this review, we will examine basic HPV epidemiology and prevalence, the molecular transformation events carried out by HPV oncoproteins, and clinical trials monitoring HPV-induced disease of the female genital tract. While precise projections of exactly how vaginal and vulvar disease prevalence will change with vaccination will require more studies, the preliminary data are promising.

Contemporary experience with the management of vulvar intraepithelial neoplasia

Experience with 40 cases of vulvar intraepithelial neoplasia seen during the 7-year period 1992-98 is detailed. The average age was 46.2 years and 27 of the patients (67.5%) were aged 50 years or younger. There was a significant association with cigarette smoking when compared with age-matched control patients attending the Vulvar Clinic with non-neoplastic conditions (67.5 vs. 12.5%; P = 0.001). Twenty-five percent of the patients had a past history of cervical intraepithelial neoplasia (CIN). The disease was multifocal in 77.5% of patients-92.6% of women aged less than 50 years and 53.8% of older women (P = 0.014). Treatment was by surgical excision supplemented in some cases by laser ablation. Occult stromal invasion was detected histologically in 15% of cases and in half of these, the invasion was to a depth considered to have significant metastatic potential. Recurrence occurred in 50% of patients and was more common in patients with multifocal disease. One patient (2.5%), aged 30, developed invasive vulvar carcinoma 4 years after treatment.

Innervated island flaps in morphofunctional vulvar reconstruction

In this article, the authors present their own experience in vulvar reconstruction following vulvectomy using two different innervated island flaps according to the size and site of the defect. Island-flap mobilization is possible thanks to the rich blood supply of the perineal region. The methods described are a "V-Y amplified sliding flap from the pubis" and a "fasciocutaneous island flap" raised from one or both gluteal folds. The V-Y amplified sliding flap from the pubis is indicated when the defect is symmetric and located anteriorly. This flap is harvested from the pubis and vascularized by the deep arterial network of the pubis. Sensory innervation is provided by branches of the ileo-inguinal nerve. The fasciocutaneous island flap, raised from one or both gluteal folds, can be used following hemivulvectomy or radical vulvectomy, respectively, to cover posteriorly located defects. Vascularization is provided by the musculocutaneous perforating branches of the pudendal artery, whereas sensory innervation is maintained through the perineal branches of the pudendal nerve. Twenty-two patients have undergone reconstructive surgery of the vulvar region from 1989 to date. On 14 patients, a V-Y amplified sliding flap was used; on 7 patients, reconstruction was carried out by island flaps raised from the gluteal fold. Both techniques are compatible with inguino-femoral lymphadenectomy, and they allow for a correct morphofunctional reconstruction and provide good local sensibility. The final result is aesthetically satisfactory, as all final scars are hidden in natural folds.

Detection of human papillomavirus in warty carcinoma of the uterine cervix: comparison of immunohistochemistry, in situ hybridization and in situ polymerase chain reaction methods

Warty carcinoma of the uterine cervix is a very rare specific variant of invasive squamous cell carcinoma, usually described as a hybrid feature of condyloma with invasive squamous cell carcinoma. Besides having the koilocytes and maturation of squamous epithelium, there is unequivocal stromal invasion. The feathery surface seems to be characteristic of warty carcinoma, differentiating it from condylomata acuminata or verrucous carcinoma. Using in situ polymerase chain reaction (IS-PCR) and in situ hybridization (ISH) as well as an immunohistochemical technique (IHC), we determined the amplification and expression of several human papilloma virus (HPV) types (6, 11, 33, 16 and 18) in nine warty carcinomas of the uterine cervix. We found amplified HPV predominantly in the nuclei of the feathery surface in all cases only when IS-PCR was applied, while it was detected only in five (55.6%) or six cases (66.7%) by conventional IHC or ISH, respectively. We found multiple types in the same lesion in six cases (66.7%) by IS-PCR, in comparison with ISH which detected a lower incidence (22.2%). This finding of coinfection is more consistent with that seen in low-grade squamous intraepithelial lesions (LSILs) of the uterine cervix than in high SIL. It is important to be aware of these distinct lesions in postmenopausal women with their characteristic feathery and thin surface, as well as a hybrid form of exophytic condyloma and stromal invasion, and frequent coinfection of multiple different HPVs as a type of LSILs.

p53 mutations and clonality in vulvar carcinomas and squamous hyperplasias: evidence suggesting that squamous hyperplasias do not serve as direct precursors of human papillomavirus-negative vulvar carcinomas

Previous studies of vulvar carcinomas have shown two distinct subsets with respect to several clinicopathologic features. In younger women, the tumors are frequently human papillomavirus (HPV) positive, are usually of basaloid or warty histology, and are associated with vulvar intraepithelial neoplasia. In older women, the tumors are usually HPV negative, are typical keratinizing squamous carcinomas, and are associated with squamous hyperplasia--a lesion that has been purported to serve as a precursor to HPV-negative invasive carcinoma. In squamous carcinomas of the cervix, p53 inactivation (through gene mutation or interaction with the HPV E6 oncoprotein) occurs in most cases. Comparatively few studies have assessed p53 mutation and HPV status in vulvar carcinomas, and none has used molecular markers to evaluate squamous hyperplasias as direct precursors of HPV-negative invasive cancers. Of 18 invasive squamous carcinomas analyzed, seven (39%) were found to be HPV positive. Four p53 gene mutations were identified--all in HPV-negative tumors. DNA was subsequently prepared from microdissected archival tissues from all four specimens showing p53 gene mutations. DNA was separately isolated from normal squamous epithelium, invasive squamous carcinoma, and associated squamous hyperplasia. In each specimen, the p53 mutation was confirmed in the invasive tumor and absent in both normal and hyperplastic epithelium. To further investigate squamous hyperplasia as a potential precursor of HPV-negative invasive carcinoma, the authors determined the clonality of hyperplastic lesions adjacent to invasive carcinomas with p53 mutation. Clonality analyses were performed using a polymerase chain reaction (PCR)-based assay for X chromosome inactivation. Although all three informative carcinomas tested were monoclonal, corresponding normal epithelia and hyperplastic lesions were polyclonal. These findings underscore the heterogeneity of vulvar cancers with respect to loss of wild type p53 function either by interaction with the HPV E6 oncoprotein or somatic mutation of p53, and suggest that squamous hyperplasias do not serve as direct precursors of HPV-negative squamous carcinomas.

Association of multiple human papillomavirus types with vulvar neoplasias

OBJECTIVE

The purpose of this study was to clarify the association of multiple genital human papillomavirus (HPV) types with vulvar neoplasias.

METHODS

We examined vulvar neoplasias by the polymerase chain reaction (PCR) method, which can detect almost all genital HPV types sensitively (L1-PCR).

RESULTS

Eight HPV types (types 6, 11, 16, 18, 52, 53, 56, and 68) were detected in 52 of 53 (98.1%) vulvar condylomas; 2 HPV types (types 16 and 18) were detected in all 6 Grade-3 vulvar intraepithelial neoplasias; and 5 HPV types (types 6, 16, 18, 51, and 56) were detected in 8 of 11 (72.7%) invasive vulvar carcinomas. Detection of HPV types 52, 53, 56, and 68 in vulvar condylomas and detection of HPV types 51 and 56 in vulvar carcinomas are the first examples ever reported.

CONCLUSION

This study suggests that more HPV types are associated with the generation of vulvar neoplasias than was thought to be the case up to now.

Multifocal vulvar intraepithelial neoplasia grade III and multicentric lower genital tract neoplasia is associated with transcriptionally active human papillomavirus

BACKGROUND

The incidence of vulvar intraepithelial neoplasia Grade III (VIN III) is increasing and is diagnosed at a younger age than previously. VIN III is often multifocal and frequently coexists with multicentric dysplastic lesions in the cervix and vagina. Warty-type VIN III more often has been found to contain human papillomavirus (HPV) DNA than basaloid-type VIN III: The authors performed HPV DNA polymerase chain reaction (PCR) analysis in 48 VIN III biopsies and reverse transcriptase (RT)-PCR in 8 HPV-16 DNA-positive multifocal VIN III biopsies to detect E6/E7 transcripts.

METHODS

Human papillomavirus DNA detection and histologic analysis were performed on alternating slides of paraffin embedded biopsies. Polymerase chain reaction was performed with consensus primers, and HPV typing was performed by direct sequencing. Total RNA was isolated from frozen biopsies by centrifuging a guanidinium thiocyanate (GTC) lysate through a cesium chloride (CsCl) cushion. The RT reaction was performed using a 3' primer, located just downstream of the E7 stop codon, and the PCR reaction was performed using the same 3' primer and a 5' primer located just downstream of the E6 start codon.

RESULTS

The mean age of the 48 patients was 37.7 years. Eighty-one percent had multifocal VIN III: Sixty-six percent had multicentric neoplasia. Forty-six percent of the biopsies were warty-type, 17% basaloid-type, 35% mixed-type and 2% differentiated-type. Ninety-two percent were HPV-positive and 83% contained HPV-16 DNA. Human papillomavirus DNA was more often present in multifocal VIN III lesions than in unifocal VIN III lesions and also more often in VIN III lesions coexisting with other dysplastic multicentric lesions than in unicentric VIN III lesions. Warty-type VIN III more often contained koilocytes than basaloid-type VIN III: A correlation between different morphologic forms of VIN III and the presence of HPV DNA was not found. Both types of VIN III often coexist in one lesion. In all the RT-PCRs, a 593-base-pair fragment was detected, corresponding to the expected length of the major E6*-E7 mRNA.

CONCLUSIONS

The observed high prevalence of transcriptionally active HPV DNA associated with multifocal and multicentric dysplasia suggests a role of HPV in the pathogenesis of these lesions. A positive correlation between different morphologic forms of VIN III and the presence of HPV DNA was not found.

Dual infection with human papillomavirus in a population with overt genital condylomas

BACKGROUND

Multiple human papillomavirus (HPV) genotypes have been demonstrated in individual patients; usually, different genotypes occur in different anatomic sites.

OBJECTIVE

Our purpose was to evaluate the prevalence of multiple HPV types from the same anatomic site.

METHODS

During the course of a study evaluating topical versus ablative therapy for external genital HPV, sequential biopsies on patients with external genital warts were performed. HPV DNA content was determined by Southern hybridization. Ninety-two specimens from 63 patients (48 women, 15 men) with genital warts were evaluated.

RESULTS

Dual infection with two HPV genotypes was documented in each of four specimens (6.3%). Sequential biopsy specimens from the same anatomic site in the same person revealed dual infection in 5 of 12 sampled patients (41%). Overall, 14% of patients had dual genitourinary HPV infection.

CONCLUSION

Counseling and follow-up of long-term complications, such as transmission and the risk of subsequent genitourinary carcinoma, should be performed on all patients with HPV because of the possibility of undetected HPV DNA types in the individual patient.

Detection of human papillomavirus types by the polymerase chain reaction and the differentiation between high-risk and low-risk cervical lesions

By means of a consensus polymerase chain reaction (PCR) method, the prevalence of HPV types was determined in cervical biopsies from 137 women referred to the gynecological outpatient clinic for colposcopy because of an abnormal cervical smear. The prevalence of HPV was 80.3%. There was a statistically highly significant rise in the prevalence of the oncogenic HPV types (16, 18, 31, 33) with increasing severity of cervical intraepithelial neoplasia (CIN I to III), indicating a role for these HPV types in the pathogenesis of cervical cancer. The prevalence of other HPV types decreased significantly with the severity of the lesion, suggesting that these HPV types play a less significant role in this process. These data indicate that HPV typing with PCR may be a valuable tool for distinguishing between high-risk and low-risk cervical lesions. Furthermore, our results suggest that the detection of HPV types by consensus PCR in the cervix of patients with an abnormal smear but without histologically detectable CIN is a useful tool for predicting which of these patients will eventually develop CIN. Finally, a relatively low percentage (3%) of HPV double infections is reported in this study.

Implication of human papillomavirus in postirradiation dysplasia

The presence of human papillomavirus (HPV) DNA and association of condylomata acuminata (CA) in the biopsy tissues of postirradiation dysplasia (PRD) of the cervix and/or vagina from 17 patients who previously had radiation therapy for malignancies of the uterine cervix, vagina, and endometrium were evaluated with DNA in situ hybridization. Eight of 17 patients (47.1%) had HPV DNA identified in the lesions of postirradiation dysplasia (PRD). Five of eight cases (62.5%) contained HPV DNA of more than one type. Type 16 HPV DNA (HPV-16) was the most frequently identified type. Several PRD lesions also contained HPV-6, HPV-18, HPV-31, and/or HPV-33 DNA. Eleven patients (64.7%) showed CA in the vicinity of PRD. In two cases, different types of HPV were found in the lesions of PRD and contiguous CA. The frequency of the cases containing HPV DNA, the types of HPV, and the distribution pattern of silver grains in the preparations of in situ hybridization over the nuclei of cells of PRD were very similar to those found in naturally occurring dysplasia. Based on these findings, persistent or repeat HPV infection was the most likely etiologic factor of PRD, which might be facilitated by immunosuppression due to pelvic irradiation.

Vulvovaginal human papillomavirus infections: clinical implications and management

The past 2 decades have witnessed an alarming increase in the incidence of human papillomavirus infections. Clinically evident cases represent only a small portion of the infected population, because millions of people have subclinical or latent infection. Human papillomavirus infection is recognized as a precursor to malignancy. Thus it is important to treat clinically evident infection. Treatment is complicated by the ability of the virus to establish latent infection and the lack of an effective antiviral agent. At present treatment is limited to the destruction of obvious and intraepithelial lesions.

Vulvar squamous cell carcinoma and papillomaviruses: two separate entities?

Vulvar squamous precancers (vulvar intraepithelial neoplasia) are associated with sexual factors, cigarette smoking, and human papillomaviruses. However, epidemiologic studies of invasive carcinoma of the vulva have produced conflicting evidence for these associations, in part because of a strong association with vulvar inflammatory disease (dystrophies) in older women. We analyzed a series of 42 vulvar invasive carcinomas for papillomavirus nucleic acids by deoxyribonucleic acid-deoxyribonucleic acid in situ hybridization and correlated their presence with age, smoking history, and morphologic type. The carcinomas were divided into well-differentiated, moderately and poorly differentiated, and intraepithelial-like growth patterns, the latter composed of nests of invasive neoplastic epithelium with preserved cell polarity, similar to intraepithelial disease. Of the lesions studied, 28% were human papillomavirus deoxyribonucleic acid-positive. Intraepithelial-like neoplasms segregated in women with a younger mean age (64 versus 73 years) than that of women with conventional squamous cell carcinoma and they more frequently had a history of cigarette smoking (88% versus 28%). Moreover, intraepithelial-like lesions contained human papillomavirus nucleic acids more frequently (67% versus 13%) when analyzed by in situ hybridization. These observations confirm the diverse nature of vulvar squamous cell carcinoma and may explain in part why conflicting results are obtained from studies investigating the role of sexual and viral factors in the genesis of vulvar cancer. They suggest that many invasive vulvar cancers may not be linked to papillomaviruses.

Clinical and histologic features of vulvar carcinomas analyzed for human papillomavirus status: evidence that squamous cell carcinoma of the vulva has more than one etiology

The association between the human papillomavirus (HPV) and malignant neoplasms of the uterine cervix is well established; however, its role in the pathogenesis of vulvar cancer has not been well defined. This study correlates the clinical and histopathologic features of 21 invasive carcinomas of the vulva with the presence of HPV DNA as detected by Southern blot and polymerase chain reaction (PCR) analysis. By one or both techniques, HPV DNA was detected in 10 of the 21 tumors analyzed; all HPVs containing tumors hybridized with HPV-16 probes, although PCR also detected HPV-6 in two of the HPV-16-containing tumors. No HPV-18 DNA was detected in any tumor by PCR or Southern blot hybridization. Both the invasive cancer and the surrounding intraepithelial disease tended to display histopathologic features that usually could distinguish HPV-associated cancers from those without HPV DNA. The intraepithelial lesions associated with HPV-containing tumors were of the bowenoid type with koilocytosis, while tumors lacking HPV generally demonstrated a simplex type of intraepithelial lesion. Invasive tumors with no viral DNA were more frequently keratinizing than the HPV-containing cancers. Race, parity, hormonal therapy, and alcohol use did not affect the HPV status; however, HPV DNA was more prevalent in the tumors of younger women and in those with a history of tobacco use. Human papillomavirus status had no impact on the stage of disease or its prognosis. These findings identify two subsets of vulvar carcinoma cases based on HPV hybridization data and the histopathologic characteristics of the tumor.

In situ hybridization analysis of human papillomavirus DNA segregation patterns in lesions of the female genital tract

Various histologic features may be used to divide human papillomavirus (HPV)-related lesions of the genital tract into two groups: condylomata and "low-grade" or grade 1 cervical intraepithelial neoplasias (CIN 1) versus "high-grade" or grade 2 and 3 intraepithelial neoplasias. Using in situ hybridization analysis we correlated HPV DNA type with histologic features in 350 biopsies of lesions from the cervix, vulva, and perianal region. HPV DNA was most commonly found in vulvar and perianal condylomata (39/46, 85%), whereas the rate in CIN 1 lesions was 72% (86/120). The rates were 53% (40/76) and 57% (12/21) in CIN 2/3 and vulvar intraepithelial neoplasm (VIN) grades 2 and 3, respectively. The HPV type in all but 2 of the 39 perianal and vulvar condylomata which contained HPV was 6/11. Despite their similar histologic features, the HPV type in only 23 of 86 (27%) CIN 1 cases with detectable HPV was 6/11 compared to 31 of 86 (36%) which contained HPV 16-related DNA and 32 of 86 (37%) which contained HPV 31,-33, or -35-related DNA. The viral DNA in the majority of CIN 2/3 lesions and all of the VIN 2/3 lesions was HPV-16 related; no CIN 2/3 or VIN 2/3 lesion had HPV 6/11-related DNA. It is concluded that although cutaneous genital tract condylomata are highly associated with HPVs of low oncogenic potential (types 6 and 11), these HPV types are not as frequent as the oncogenic HPVs (16, 31, 33, and 35) in CIN 1 lesions. Further, HPV 6/11 appears to be very rarely associated with CIN 2/3 or VIN 2/3 lesions.