Vaginal Intraepithelial Neoplasia and Vaginal Cancer : A Clinical and Histopathological Review of Rare Yet Rising Entities

Abstract

Vaginal intraepithelial neoplasia (VaIN) and primary vaginal malignancies represent a rare subset of lower genital tract neoplasms, accounting for approximately 1% of all gynecological cancers. VaIN, a precursor lesion with substantial oncogenic potential, remains a diagnostic and therapeutic challenge. Its incidence is increasing due to heightened awareness, expanded cytologic and HPV screening, and routine colposcopic evaluation. Risk factors include prior cervical intraepithelial neoplasia, hysterectomy for CIN, immunosuppression, prior pelvic irradiation, persistent high-risk HPV infection, smoking, HIV, and diethylstilbestrol (DES) exposure. The vaginal microbiome's composition is increasingly recognized as a determinant of host susceptibility to HPV and neoplastic transformation.

The Lower Anogenital Squamous Terminology (LAST) classifies VaIN into low-grade (VaIN 1) and high-grade squamous intraepithelial lesions (VaIN 2 and 3), with the latter harboring a significant risk of progression to invasive disease. High-grade VaIN necessitates definitive treatment, whereas low-grade lesions may be monitored. Therapeutic modalities include wide local excision, laser ablation, LEEP, and in select cases, upper vaginectomy. Non-excisional therapies such as CO₂ laser vaporization, photodynamic therapy, and plasma energy ablation are feasible in the absence of invasion. The choice of treatment should be individualized based on lesion extent, visualization, and prior therapies. Recurrence is not uncommon, warranting vigilant long-term surveillance.

Primary vaginal carcinomas, chiefly squamous cell in origin, are staged clinically using FIGO and TNM classifications. Definitive management involves external beam radiotherapy (EBRT) with concurrent chemotherapy, followed by image-guided adaptive brachytherapy. Prognosis is primarily stage-dependent. Uncommon histologic subtypes such as vaginal melanoma and sarcomas pose unique diagnostic and therapeutic considerations due to their aggressive nature and rarity.

This review consolidates the evolving landscape of VaIN and vaginal cancer, emphasizing diagnostic standardization, risk stratification, and a tailored multimodal treatment paradigm aligned with contemporary oncologic principles.