Anal Squamous Intraepithelial Neoplasia
Anal squamous intraepithelial lesions (ASILs) are part of the multicentric infection of the lower genital tract by the human papillomavirus (HPV). The rate of anal cancer during 2004–2008 in the United States among females was 1.8 per 100,000 and 1.2 per
- PDF / 303,828 Bytes
- 5 Pages / 504.567 x 720 pts Page_size
- 24 Downloads / 196 Views
56
Silvio Tatti, Veronica Suzuki, and Laura Fleider
56.1 Epidemiology Anal squamous intraepithelial lesions (ASILs) are part of the multicentric infection of the lower genital tract caused by the human papillomavirus (HPV). The term anal squamous intraepithelial lesions correlates with the Bethesda classification used for cervical lesions and is also subdivided into high-grade and low-grade lesions—this also applies using the LAST terminology, a unified and standardized nomenclature recommended for all HPV-associated squamous lesions of the lower anogenital tract [1]. The exact natural history of ASIL is not known, but it is widely believed that high-grade ASILs are considered potentially malignant and can progress to anal carcinoma, similar to the natural history of high-grade cervical lesions that can progress to cervical cancer [2, 3]. There are biological, epidemiological, and histological similarities between anal cancer and cervical cancer. Etiopathogenic characteristics include the association with an infection caused by the HPV, especially HPV16. Eighty-eight percent of anal carcinomas are associated with some type of HPV infection (73% HPV16 and 7% HPV18) [4, 5]. The cervix and anus both have a transformation zone where the squamous and columnar epithelium joins. The mucosa of the S. Tatti (*) · V. Suzuki · L. Fleider Argentina Hospital de Clinicas “Jose de San Martin”, University of Buenos Aires, Buenos Aires, Argentina
anal canal joins the squamous epithelium in the dentate line where we can find more intraepithelial lesions [6]. The rate of anal cancer during 2004–2008 in the United States among females was 1.8 per 100,000 and 1.2 per 100,000 among males [7]. Anal carcinoma and their precursor lesions have increased in the last decades, especially among men who have sex with men (MSM), renal transplant, and other causes of immunosuppression. Women with human immunodeficiency virus (HIV) infection have a higher risk compared to the general population. When highly active antiretroviral therapy (HAART) was introduced in 1996, the incidence did not decrease [8].
56.2 Risk Factors The main risk factors described for HPV infection include multiple viral types involved and high oncogenic risk HPV, also HIV infection and low CD4+ count, history of genital warts, and anal sexual intercourses. Other risk factors include smoking, chronic immunosuppression such as receiving treatment with high-dose corticosteroids or solid organ transplants, or presence of other anogenital HPV lesions [9–14]. Men who have sex with men (MSM) and HIV-positive patients constitute a risk group. Non- immunosuppressed women with lower genital tract disease may also have ASIL.
© Springer International Publishing AG, part of Springer Nature 2019 J. Bornstein (ed.), Vulvar Disease, https://doi.org/10.1007/978-3-319-61621-6_56
379
S. Tatti et al.
380
Regarding the association between ASIL and other intraepithelial lesions of the lower genital tract, Scholefield et al. described 29 (19%) of 152 women with cervical intraepithelial
Data Loading...
