Laparoscopic abdominoperineal resection after preoperative chemoradiotherapy for advanced carcinoma associated with anal fistula

: The patient was a 71-year-old man who was diagnosed with anal fistula 50 years previously. He complained of mucous and bloody stools. He was diagnosed with a carcinoma associated with anal fistula after biopsy. Image examination showed that the tumor was filled with mucinous substances and that it had invaded the levator ani muscle, with left external iliac and left inguinal lymph node metastases. Therefore, preoperative chemoradiotherapy for locally advanced cancer was administered. After chemoradiotherapy, the tumor and metastatic lymph nodes reduced in size. We performed laparoscopic abdominoperineal resection. Histopathologically, the tumor was revealed as a mucinous adenocarcinoma, but no cancer cells were present on the surgical margin. This case suggested that preoperative chemoradiotherapy could be effective for locally advanced carcinoma associated with anal fistula.