anal intraepithelial neoplasia


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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 ?
Summary of studies focused on effectiveness of different treatment modalities of anal intraepithelial neoplasia (AIN).
Major Finding: The quadrivalent HPV vaccine had 77.5% efficacy in preventing anal intraepithelial neoplasia, including condyloma, and it had 94.9% efficacy in preventing persistent anal HPV infection, in the per-protocol study population.
Data Source: A randomized, double-blind trial comparing the efficacy of the quadrivalent HPV vaccine against placebo at preventing anal intraepithelial neoplasia in 598 healthy homosexual men in seven countries who were followed for approximately 3 years.
RISK FACTORS IMPLICATED IN ANAL INTRAEPITHELIAL NEOPLASIA
Several studies were conducted in order to identify risk factors for developing anal intraepithelial neoplasia and abnormal anal cytology.
AIN, anal intraepithelial neoplasia; p-y, person-years.
Individuals infected by the human immunodeficiency virus (HIV) have a high risk of infection by human papillomavirus (HPV), as well as a high incidence of anal intraepithelial neoplasia (AIN) and anal cancer caused by HPV [1].
Detection of human papillomavirus DNA in anal intraepithelial neoplasia and anal cancer.
Conventionally, lesions involving the former have been termed dysplasia, in situ carcinoma, or anal intraepithelial neoplasia, whereas lesions involving the skin, Bowen disease.
Men who have sex with men (MSM) are particularly at risk for conditions associated with HPV types 6, 11, 16, and 18; diseases and cancers that have a higher incidence among MSM include anal intraepithelial neoplasias, anal cancers, and genital warts (8,9).