Catherine M. McLachlin

PATHOBIOLOGY OF VULVAR SQUAMOUS NEOPLASIA

Vulvar squamous carcinoma is an uncommon neoplasm that afflicts a spectrum of women and has been associated with granulomatous vulvar diseases, papillomaviruses, and chronic inflammatory disorders of the vulva. Histopathological, molecular, and epidemiological studies have revealed two subsets of vulvar squamous neoplasia, which are distinguished by their association with human papillomaviruses and patient demographics. This review summarizes the evidence both supporting the diverse pathogenesis of these tumors and the existence of factors that may be common to both groups. Ultimately, the pathway to both human papillomavirus positive and negative vulvar cancers may involve not only obvious precancerous changes but also biological events in the vulvar mucosa that precede the onset of morphological atypia.

Histologic Correlates of Vulvar Human Papillomavirus Infection in Children and Young Adults

Two clinically important issues in the treatment of vulvar wartlike lesions are the histologic criteria for the recognition of human papilloma virus (HPV)-related lesions and the exclusion of lesions derived from cutaneous rather than genital HPV types. We analyzed a series of 70 biopsies from the vulva or distal vagina of 57 children and 13 young adults for HPV nucleic acids by polymerase chain reaction (PCR) amplification and typed the isolates following isotope labeling and restriction digestion (restriction fragment length polymorphism [RFLP] analysis). Lesions were classified as condyloma, suggestive of condyloma (papillary/verrucous architecture without koilocytotic atypia), or nonspecific epithelial alterations. Three observers independently agreed on the presence of papillary/verrucous architecture and koilocytotic atypia with a high degree of concordance (kappa = 0.74 and 0.71, respectively). By RFLP analysis, 77% of the lesions diagnosed as condyloma and 68% of those diagnosed as suggestive of condyloma contained HPV nucleic acids versus 9% of the nonspecific group. The HPV types identified were HPV 6 (67%), HPV 11 (17%), HPV 16 (3%), and unknown types (14%). No cutaneous HPV types were identified. Three patients with unknown HPV types had a history of sexual abuse, implying a genital source. These findings indicate that verrucopapillary external genital lesions, as defined in this report, are likely to be associated with HPV and that the vast majority contain genital HPV types irrespective of histologic presentation.

Multinucleated Atypia of the Vulva Report of a Distinct Entity Not Associated with Human Papillomavirus

The vulvar mucosa often demonstrates epithelial nuclear atypia in association with reactive and inflammatory conditions. These nuclear changes are usually mild and can be readily distinguished from vulvar intraepithelial neo-plasia (VIN) and human papillomavirus (HPV)-related lesions. In a recent survey of vulvar biopsies in reproductive-aged women, we identified 12 cases of an unusual pattern of atypia associated with multinucleated epithelial cells but lacking the usual stigmata of reactive changes, condyloma, or VIN. The average age of the patients with multinucleated atypia of the vulva (MAV) was 37 years. The multinucleated cells were commonly in the lower to middle epithelial layers and contained between two and 10 nuclei, often with prominent nucleoli. In contrast to condyloma and VIN, there was no surface atypia, and the multinucleated cells lacked hyperchromasia, irregularity, or variation in nuclear size. No significant inflammation or identifiable infectious process was present, and none of the patients had received any topical treatment other than mild corticosteroids. Two of the patients had a history of VIN at a noncontiguous site. None of the 12 cases contained HPV DNA by either in situ hybridization or polymerase chain reaction (PCR) restriction fragment length polymorphism (RFLP) analysis. This is in contrast to 49 of 65 women with VIN and 21 of 26 with condyloma who had HPV demonstrable by the PCR method (p < 0.00001). Immunoperoxidase stains for herpes types I and II were also negative in all the cases. Thus, MAV appears to be a distinct entity occurring in relatively young women; when it is not associated with condyloma or VIN, MAV is not related to HPV. As the morphologic features may overlap with both condyloma and VIN, it is important that MAV not be confused with these lesions or vice versa. It is not known whether MAV is a risk factor for VIN, represents an exaggerated reactive response, or is an entity with a distinct origin.

Disparities in mean age and histopathologic grade between human papillomavirus type-specific early cervical neoplasms

Noninvasive squamous and glandular precursor lesions associated with human papillomavirus (HPV) types 16 and 18 have been reported to vary in morphology. HPV 16 is associated predominantly with high-grade squamous intraepithelial lesions (HSIL; cervical intraepithelial neoplasia (CIN 2 and 3), and HPV 18 is associated with low-grade squamous intraepithelial lesions (condyloma/CIN 1) and CIN 3/adenocarcinoma in situ (ACIS). This study explored the relationship of morphologic growth pattern in these precursor groups with age of presentation. One hundred fourteen CIN lesions (including those with ACIS), associated with HPV 16 or 18, were subdivided into well-differentiated low- and high-grade SIL (CIN 1 and 2, respectively), poorly differentiated HSIL (CIN 3) with or without ACIS. HPV was detected by polymerase chain reaction (PCR) amplification with L1 consensus or type-specific E7 primers and typed by restriction fragment length polymorphism (RFLP) analysis. Age of the patient was obtained from the pathology report. Mean age for each group was as follows: Low-risk HPVs, 25 years; HPV 18 CIN 1-2, 21.6 yrs; HPV 18 CIN 3/ACIS, 35.2 yrs; HPV 16 CIN 1,2, 25.9 yrs; and HPV 16 CIN 3, 29.8 yrs. There were significant differences in mean ages between HPV 18 CIN 1 and 2 and HPV 16 CIN 1 to 2 (P = .04), HPV 16 CIN 1-2 and CIN 3 (P = .01) and HPV 18 CIN 1 to 2 and HPV 18 CIN 3/ACIS (P = .00001). None of the cases of HPV 18-associated CIN3/ACIS was associated with a CINI lesion. The disparity in mean ages between well and poorly differentiated HPV 16/18 related that precursor lesions could reflect factors such as morphologic progression with increasing age, different rates of lesion persistence, depending on grade, or efficiency of detection between the two groups. The marked difference in mean age between HPV 18-associated CIN 1-2 and CIN 3/ACIS, combined with their lack of coexistence in the same cervix, raises alternate possibilities that specific viral or host factors may determine the morphological phenotype associated with some HPV 18 infections. In the latter, the possibility that age independently confers an increased risk for higher-grade lesions should be considered.

Prevalence and histologic significance of cervical human papillomavirus DNA detected in women at low and high risk for cervical neoplasia

Objectives To determine and compare the prevalence and histologic significance of human papillomavirus (HPV) nucleic acids in cervical specimens from women at low (routine hysterectomy) and high (suspicion of cervical neoplasia) risk for cervical neoplasia. Methods Cervical brushings were taken from the cervices of hysterectomy and conization or loop electrical excision specimens and analyzed for HPV nucleic acids by polymerase chain reaction and restriction fragment length polymorphism analysis. Histopathology was confirmed by review of reports or, for HPV-positive results, re-review of the histopathology. Statistical analysis used Student t test or Fisher exact test. Results Four hundred seventeen and 43 low- and high-risk cervices, respectively, were studied. Statistically significant differences were observed in the index of HPV positivity between the low- and high-risk groups (1.7 versus 42%, P < .001) and the proportion of HPV being cancerassociated HPV types (14 versus 78%, P = .005). None of the 417 cervices from low-risk women contained HPV 16. In the high-risk group, histologically confirmed cervical intraepithelial neoplasia lesion was statistically more likely to be associated with HPV (59 versus 13%, P = .005). Conclusion Cervices from routine, low-risk hysterectomies in predominately middle-aged women have an extremely low index of cancer-associated HPVs. Considering the strong association of HPV with histologically proven disease, prospective studies exploring the relationship of cancer-associated HPVs to neoplasia in middle-aged women merit consideration.

Pathology of human papillomavirus in the female genital tract.

Human papillomavirus (HPV) has emerged as a major factor in the genesis of intraepithelial and invasive neoplasms of the female genital tract. The strength of the relationship of HPV to genital neoplasia has been supported by studies involving epidemiologic, clinical, pathologic and molecular data. The many subtypes of HPV have been characterized into risk groups that reflect their propensity to be associated with cancer precursors and invasive disease. The strong correlation between HPV and squamous dysplasia suggests that classification of cervical intraepithelial lesions into similar risk categories should be possible. However, the clinical predictive value of HPV testing and typing remains controversial.