anal intraepithelial neoplasia

(redirected from Anal Squamous Intraepithelial Lesions)
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anal intraepithelial neoplasia

A carcinoma in situ of the anorectal mucosa that is embryologically, histologically, and pathologically analogous to cervical intraepithelial neoplasia, which is linked to HPV infection and divided into low-grade (LG-AIN) and high-grade (HG-AIN) tumours, the latter of which is associated with aggressive squamous cell carcinoma.

Risk factors
Anal HPV infections, receptive anal intercourse, HIV infection and decreased CD4-+ve T cells.
 
HPV types
6/11, 31/33/35 and 16/18.

anal intraepithelial neoplasia

Abbreviation: AIN
A precancerous change in the squamous cells of the anus that may eventually develop into anorectal cancer. It is similar to cervical intraepithelial neoplasia in that it is a premalignant lesion that arises in squamous cells, is found primarily in sexually active people, and is associated with human papillomavirus and HIV.
Synonym: anal dysplasia; anal squamous intraepithelial lesion
See also: neoplasia
References in periodicals archive ?
Infrared coagulator ablation of high-grade anal squamous intraepithelial lesions in HIV-negative males who have sex with males.
Prevalence and risk factors for anal squamous intraepithelial lesions in women.
Effect of highly active antiretroviral therapy on the natural history of anal squamous intraepithelial lesions and anal human papillomavirus infection.