[Nomenclature of squamous cell precursor lesions of the lower female genital tract : Current aspects].

The majority of precancerous lesions of the lower female genital tract (intraepithelial neoplasia, IN) are caused by human papillomavirus (HPV) infections resulting in cellular atypia and in turn an altered tissue architecture. Depending on the pathogenesis, a distinction is made between vulvar intraepithelial neoplasia (VIN) classified as classical VIN associated with high-risk HPV infections (u-VIN) and differentiated VIN (d-VIN), which is associated with lichen sclerosus et atrophicus and p53 alterations. In the current World Health Organization (WHO) classification a novel grading system for squamous cell precancerous lesions of the lower female genital tract has been proposed, differentiating low grade squamous intraepithelial lesions (L-SIL) including condyloma and HPV-associated alterations plus VIN 1, vaginal intraepithelial neoplasia (VaIN 1) and cervical intraepithelial neoplasia (CIN 1) from high grade squamous intraepithelial lesions (H-SIL) with VIN 2 and 3, VaIN 2 and 3 as well as CIN 2 and 3. The use of p16 immunohistochemistry can assist the differentiation. The new binary classification, however, contradicts the German cytological nomenclature (Munich nomenclature III), which differentiated three grades of dysplasia in order to avoid overtreatment of patients with moderate IN. The individual nomenclatures are compared to each other. It is recommended to report the grade of precancerous lesions in addition to the SIL classification of the WHO.