Detection rate and clinical characteristics of vulvar squamous intraepithelial lesion

Abstract

Objective: To explore the detection rate, clinical characteristics of vulvar squamous intraepithelial lesion (SIL). Methods: Women diagnosed with vulvar high-grade squamous intraepithelial lesions (HSIL) through colposcopy-guided biopsy from January 1, 2018 to August 31, 2022 in Obstetrics and Gynecology Hospital of Fudan University were included in a 1∶1 ratio with patients diagnosed with vulvar low-grade squamous intraepithelial lesions (LSIL) during the same period. Clinical characteristics including human papillomavirus (HPV) infection rate, genotype, cytology result, colposcopy impression, and lesion location were retrospectively analyzed. Results: (1) The proportion of vulvar SIL detected by colposcopy-guided biopsy increased annually from 2018 to 2022, with rates of 1.64% (740/45 057), 2.34% (1 110/47 402), 2.68% (1 108/41 335), 3.26% (1 536/47 078), 3.31% (667/20 155), with an average rate of 2.57% (5 161/201 027). (2) A total of 1 096 cases of vulvar HSIL and 1 096 cases of vulvar LSIL were included. The overall infection rate of HPV was 92.7% (1 993/2 150), with higher infection rate in vulvar HSIL patients than that in vulvar LSIL patients [96.0% (1 012/1 054) vs 89.5% (981/1 096); χ2=33.62, P<0.001]. Among vulvar HSIL patients, the common HPV genotype from high to low were HPV 16 (66.7%), HPV 52 (14.3%), and HPV 58 (10.0%). For vulvar LSIL patients, the most common HPV genotype were respectively HPV 16 (24.9%), HPV 6 (20.1%) and HPV 52 (17.1%). The overall sensitivity rate of cytology was 53.6%, with no significance difference between vulvar LSIL and HSIL groups (54.3% vs 52.9%; χ2=0.40, P=0.526). The accuracy of colposcopy impression for vulvar HSIL was lower than that for vulvar LSIL [40.2% (163/405) vs 81.7% (380/465); χ2=158.72, P<0.001]. About 57.3% (1 257/2 192) of the patients had concomitant cervical and vaginal lesions, with a higher rate in vulvar HSIL group than that in vulvar LSIL group [62.6% (686/1 096) vs 52.1% (571/1 096); χ2=24.67, P<0.001]. Unifocal lesion was the main type, with no significance difference between vulvar LSIL and HSIL groups [81.4% (381/468) vs 82.5% (386/468); χ2=0.18, P=0.671]. The most common lesion locations were the posterior commissure, followed by labia minora, vaginal vestibule, labia majora, perianal and clitoris. Conclusions: The detection rate of vulvar SIL under colposcopy is about 3%, and the infection rate of HPV is 92.7%. Vulvar SIL, especially vulvar HSIL, is likely to cause concomitant cervical and vaginal lesions. The accuracy of colposcopy in diagnosing vulvar HSIL is low. Therefore a comprehensive and careful examination of the vulva is necessary and suspicious vulvar lesions should be undergone colposcopy-guided biopsy for diagnosis.