[A Case of Anal Canal Cancer with Pagetoid Spread and a Significant Response to Preoperative Chemoradiotherapy].

Perianal Pagetoid spread is a rare condition for which there is no proven therapy. We experienced a case of anal canal cancer with Pagetoid spread which exhibited a significant response to preoperative chemoradiotherapy(CRT). A 76-year-old man with anal stenosis was referred to our hospital. He was diagnosed with anal canal cancer with Pagetoid spread. No infiltration into the surrounding tissue was observed, but metastasis to the left inguinal lymph node was noted. The patient received preoperative CRT(oral S-1, 1.8 Gy×25 Fr, a total dose of 45 Gy)including the bilateral inguinal region. After CRT, the main tumor size was reduced and PET-CT showed disappearance of the abnormal accumulation in the left inguinal lymph nodes. Laparoscopic abdominoperineal resection and left inguinal trans lymphadenectomy were performed. The macroscopic findings of the surgical specimen confirmed no residual carcinoma or lymph node metastasis. Although more proof is needed, this case suggested that CRT may be effective for anal canal cancer with pagetoid spread.