An Update on Vulvar Intraepithelial Neoplasia
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.
Vulvar squamous cell carcinoma (SCC) is an uncommon malignant neoplasm which represents approximately 4% of all genital cancers in women, but accounts for >90% of vulvar malignant tumours. Two-thirds of cases occur in women older than 60 years. There are two distinct types of vulvar intraepithelial neoplasia (VIN), which differ from each other in terms of aetiology, pathogenesis and clinical significance. One form is associated with high-risk human papilloma virus (HPV) infection, which gives rise to basaloid or warty SCCs and the second is associated with chronic inflammatory skin conditions, independent of HPV infection, often driven by p53 mutations and a precursor of keratinizing SCCs.
In 2004 the International Society for the Study of Vulvar Disease (ISSVD) introduced the current two-tier classification for VIN. On one hand is the HPV-associated classic or usual VIN (uVIN), which encompasses high-grade lesions (VIN 2–3). The classification did not include grading of VIN and lesions formerly called VIN1 were placed in the condyloma acuminata category. The second VIN type is the HPV-independent differentiated or simplex-type VIN (dVIN). dVIN is considered to be a high-grade lesion, and therefore is not graded.
Abstract and Introduction
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.
Introduction
Vulvar squamous cell carcinoma (SCC) is an uncommon malignant neoplasm which represents approximately 4% of all genital cancers in women, but accounts for >90% of vulvar malignant tumours. Two-thirds of cases occur in women older than 60 years. There are two distinct types of vulvar intraepithelial neoplasia (VIN), which differ from each other in terms of aetiology, pathogenesis and clinical significance. One form is associated with high-risk human papilloma virus (HPV) infection, which gives rise to basaloid or warty SCCs and the second is associated with chronic inflammatory skin conditions, independent of HPV infection, often driven by p53 mutations and a precursor of keratinizing SCCs.
In 2004 the International Society for the Study of Vulvar Disease (ISSVD) introduced the current two-tier classification for VIN. On one hand is the HPV-associated classic or usual VIN (uVIN), which encompasses high-grade lesions (VIN 2–3). The classification did not include grading of VIN and lesions formerly called VIN1 were placed in the condyloma acuminata category. The second VIN type is the HPV-independent differentiated or simplex-type VIN (dVIN). dVIN is considered to be a high-grade lesion, and therefore is not graded.
Source...