Review
Copyright ©The Author(s) 2024.
World J Exp Med. Sep 20, 2024; 14(3): 98525
Published online Sep 20, 2024. doi: 10.5493/wjem.v14.i3.98525
Table 2 World Health Organization histological classification of anal tumors
Tumor type
Characteristics
Epithelial tumors
    Premalignant lesionsIntraepithelial neoplasia (dysplasia), low-grade
Intraepithelial neoplasia (dysplasia), high-grade
Bowden disease
Perianal squamous intraepithelial neoplasia
Paget disease
    CarcinomaSquamous cell carcinoma
Adenocarcinoma
Mucinous adenocarcinoma
Small cell carcinoma
Undifferentiated carcinoma
Others
Nonepithelial tumorsLeiomyoma
Gastrointestinal stromal tumor
Myofibroma
Carcinoid tumorsNA
MelanomaNA
Secondary tumorsDirect extension from adjacent organs: Rectal, cervical, and prostate carcinoma