Two types of vulvar squamous cell carcinomas (VSCCs) are recognized according to their relationship to human papillomavirus (HPV). Basaloid or warty carcinomas are considered HPV-associated tumors, whereas differentiated keratinizing neoplasms are considered non-HPV-associated. Recently, immunohistochemical detection of p16 and p53 has been proposed to differentiate these 2 types of VSCCs. We conducted a histologic study with immunohistochemical evaluation of p16 and p53 and HPV detection and typing by polymerase chain reaction using 2 different sets of primers in 92 cases of VSCCs to evaluate the usefulness of immunohistochemistry in the classification of VSCCs and to describe the clinico-pathologic characteristics of both types of VSCCs. HPV was detected in 16/92 (17.4%) specimens, HPV16 being identified in 75% of positive cases. A significant number of discrepancies between histology and HPV detection were observed, with 37.5% of HPV-positive tumors being keratinizing and 9.2% of HPV-negative carcinomas showing basaloid or warty features. Diffuse positivity for p16 and p53 was observed in 100% and 6.2% of HPV-positive tumors and in 2.3% and 64.5% of HPV-negative neoplasms, respectively. The sensitivity and specificity of p16 immunostaining to detect HPV-associated carcinomas (100% and 98.7%, respectively) were better than those of histologic criteria (93.8% and 35.5%) and of p53 negative stain (62.5% and 93.4%). Vulvar intraepithelial neoplasia grade 3 of basaloid/warty type was identified in 53.8% HPV-positive tumors, including 3 keratinizing tumors. All these cases were p16 positive and p53 negative. Vulvar intraepithelial neoplasia grade 3 of differentiated type was observed in 45.6% of HPV-negative cases; 90.8% of them were positive for p53 but all were negative for p16. No differences in age, stage, or development of recurrence were observed between HPV-positive and negative tumors. In summary, the current morphologic criteria to discriminate HPV-positive and negative VSCCs have a significant overlap. Immunostaining for p16 is a reliable marker for HPV-positive VSSCs, which improves the results of histologic classification.

Objective: To assess the natural evolution of low-grade squamous intraepithelial lesions (LSIL) in a retrospective study conducted in a specialized primary care setting of patients detected from the cervical cancer prevention program. Materials and Methods: A review of all cytological examinations between January and December 2002, with 24 months follow-up was conducted in LSIL patients. Follow-up with cytological testing and colposcopy were performed every 6 months, and a biopsy was performed in cases that were indicated by protocol. Patients were not systemically or topically treated in any case. Results: During the study period, 4,152 women received cytology testing, and 122 had LSIL (prevalence, 2.9%). One hundred eleven patients (91%) completed the follow-up, and the remaining patients were lost for various reasons. The age distribution was as follows: 3.2% (G20 years), 34.4% (20Y29 years), 25.4% (30Y39 years), 27.2% (40Y49 years), 9% (50Y59 years), and 0.8% (960 years). Spontaneous regression was observed in 79 (71.3%) of women who completed follow-up. Regression was observed in 51.8% of patients within 12Y18 months and in 48.2% of patients within 18Y24 months of cytological testing. Regression according to age group was as follows: 100% (G20 years), 79.5% (20Y29 years), 60.6% (30Y39 years), 81.8% (40Y49 years), 90.9% (50Y59 years), and 100% (960 years). Conclusions: The general tendency of natural regression in LSIL patients without any specific risk factors identified is supported by our results. 2007, American Society for Colposcopy and Cervical Pathology