Human Papillomavirus‐Associated Risk Factors and Clinical Characteristics of Vaginal Intraepithelial Neoplasia: A Retrospective Study

Vaginal intraepithelial neoplasia (VaIN) is a rare premalignant lesion with the potential to progress to invasive vaginal carcinoma, yet its clinical characteristics and associated risk factors remain incompletely defined. This retrospective study evaluated the prevalence, human papillomavirus (HPV) genotype distribution, and clinical risk factors of VaIN in women undergoing colposcopy. A total of 8206 patients who received colposcopic examination and vaginal biopsy due to abnormal ThinPrep cytologic test results and/or high-risk HPV positivity between January 2021 and December 2023 were reviewed. Patients with cervical cancer, vulvar intraepithelial lesions, or condyloma acuminatum were excluded. Clinical characteristics, HPV genotypes, cytology findings, and histopathological results were analyzed. VaIN was diagnosed in 682 patients (8.22%). The most prevalent HPV genotypes were HPV16, HPV52, HPV58, and HPV53. High-grade VaIN (VaIN3) occurred more frequently in older and postmenopausal women. Concurrent VaIN and cervical intraepithelial neoplasia was significantly associated with advanced age, postmenopausal status, multiple HPV infections, and a history of cervical intraepithelial neoplasia. Among women with prior hysterectomy, VaIN was more commonly observed after hysterectomy for cervical lesions, although 24.7% of cases followed hysterectomy for non-cervical indications. In non-hysterectomized patients, 98.2% of VaIN lesions were located in the upper third of the vagina. Multivariate analysis identified older age, postmenopausal status, and multiple HPV infections as independent risk factors for VaIN. These findings underscore the importance of vigilant vaginal surveillance, particularly in women with persistent or multiple HPV infections and those with a history of hysterectomy.