Vulvar intraepithelial neoplasia and vulvar squamous cell carcinoma: a clinicopathologic study of 18 cases

Background: The vulvar intraepithelial neoplasia is divided into two groups: usual type and differentiated type. The differentiated vulvar intraepithelial neoplasia which is frequently seen together with the invasive squamous cell carcinoma can be confused with some benign lesions. To analyse p16, p53, and Ki-67 expression characteristics of different histological types of invasive squamous cell carcinoma of the vulva and vulvar intraepithelial neoplasia is aimed in this study.Methods: In this study, immunohistochemical analysis of 18 vulvectomy cases with p16, p53, and Ki-67 was performed.Results: Of 18 patient who underwent vulvectomy, 9 had invasive squamous cell carcinoma and 9 vulvar intraepithelial neoplasia. 3 additional vulvar intraepithelial neoplasia lesions were found accompanying the invasive squamous cell carcinomas. Mean Ki-67 PI was 32,3% in usual type (human papilloma virus-related) vulvar intraepithelial neoplasia cases (n:9), and 26,4% in differentiated vulvar intraepithelial neoplasia cases (n:3)(p>0,05). Mean p16 staining degree was 2,6 for usual type vulvar intraepithelial neoplasias. No p53 expression was present in squamous cell hyperplasia or lichen sclerosis lesions.Conclusions: Ki-67 PI does not have significant value in recognizing vulvar intraepithelial neoplasia usual type and differentiated vulvar intraepithelial neoplasia. p53 positivity can be of value in distinguishing especially differentiated type vulvar intraepithelial neoplasia from benign lesions.