title: An update on vulvar intraepithelial neoplasia: terminology and a practical approach to diagnosis.
abstract: There are two distinct types of vulvar intraepithelial neoplasia (VIN), which differ in their clinical presentation, aetiology, pathogenesis and histological/immunophenotypical features. One form driven by high-risk human papilloma virus infection usually occurs in young women and has been termed classic or usual VIN (uVIN). The other, not related to viral infection, occurs in postmenopausal women with chronic skin conditions such as lichen sclerosus and lichen simplex chronicus and is termed differentiated or simplex-type VIN. The latter is the precursor lesion of the most common type of squamous cell carcinoma (SCC) in the vulva, namely keratinizing SCC (representing 60% of cases). In contrast, uVIN usually gives rise to basaloid or warty SCC (40% of cases). The histological features of uVIN are similar to those of high grade lesions encountered in other lower anogenital tract sites (hyperchomatic nuclei with high nuclear to cytoplasmic ratios and increased mitotic activity). However, differentiated VIN has very subtle histopathological changes and often escapes diagnosis. Since uVIN is driven by high-risk human papilloma virus infections, p16 immunohistochemistry is diffusely positive in these lesions and is characterized with a high Ki-67 proliferation index. In contrast, differentiated or simplex-type VIN is consistently negative for p16 and the majority of the cases harbour TP53 mutations, correlating with p53 positivity by immunohistochemistry.
authors.affiliation: Department of Pathology and Laboratory Medicine, University of Pennsylvania, , Philadelphia, Pennsylvania, USA.
authors.forename: M Carolina
authors.initials: MC
authors.lastname: Reyes
authors.forename: Kumarasen
authors.initials: K
authors.lastname: Cooper
mesh_terms: D000328:Adult; D000368:Aged; D002278:Carcinoma in Situ / Q000378:metabolism / Q000473:pathology* / Q000821:virology; D002294:Carcinoma, Squamous Cell / Q000378:metabolism / Q000473:pathology* / Q000821:virology; D002467:Cell Nucleus / Q000378:metabolism; D019941:Cyclin-Dependent Kinase Inhibitor p16; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000378:metabolism; D008875:Middle Aged; D060787:Neoplasm Grading; D009363:Neoplasm Proteins / Q000378:metabolism; D009450:Neurodermatitis / Q000378:metabolism / Q000473:pathology* / Q000821:virology; D030361:Papillomavirus Infections / Q000378:metabolism / Q000473:pathology* / Q000821:virology; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D007724:Vulvar Lichen Sclerosus / Q000378:metabolism / Q000473:pathology* / Q000821:virology; D014846:Vulvar Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000821:virology
chemical_list: C000614131:CDKN2A protein, human; D019941:Cyclin-Dependent Kinase Inhibitor p16; D019394:Ki-67 Antigen; D009363:Neoplasm Proteins; D016159:Tumor Suppressor Protein p53
keywords: GYNAECOLOGICAL PATHOLOGY; KI 67; P53