Diagnosis and Treatment of Anal Squamous Cell Carcinoma.

A 61-year-old woman with ongoing tobacco use was referred to a colorectal surgery clinic after a screening colonoscopy found irregular lesions at the dentate line with biopsies revealing a high-grade squamous intraepithelial lesion. She reported scant bleeding and irregular bowel function, but no incontinence. She has a history of abnormal Papanicolaou tests, but has since undergone a hysterectomy and has no history of immunosuppressive treatment or HIV. She was taken for an examination under anesthesia that revealing a 2.5-cm mass in the anal canal and was biopsied. Pathological examination confirmed anal squamous cell carcinoma (ASCC) with strongly positive p16 staining. A CT of her chest, abdomen, and pelvis did not reveal metastatic disease. She was referred to medical and radiation oncology for radiation therapy with concurrent chemotherapy (5-fluorouracil (5-FU) and mitomycin C). Subsequent office examination with anoscopy 3 months after treatment demonstrated an anterior scar without residual tumor.