<unk>  is a pre-cancerous condition which occurs when the lining of the anal canal undergoes abnormal changes. It can be classified as low-grade squamous intraepithelial lesions (LSIL) and high-grade squamous intraepithelial lesions (HSIL)   
Most cases are not associated with symptoms, but people may notice lumps in and around the anus.broken link
Anal dysplasia
Anal fissure
Anal fissure pathophysiology
Anal fistula pathophysiology
Genital ulcer disease
Anal fistula
Anal abscess
Rectal prolapse