Abstract
A 68-year-old man had a more than 10-year history of anal fistula. He presented with bilateral scrotal abscess and visited our hospital. Multiple secondary orifices were observed in the perianal region, and urethral stricture and pyuria were noted. Carcinoma associated with anal fistula was suspected, but malignant cells were not detected by cytodiagnosis of the secondary orifices and endoscopic biopsy. We performed seton drainage to improve inflammation. We diagnosed adenocarcinoma on analysis of a biopsy specimen from the fistula wall at that time. Pelvic CT and MRI showed invasion of the prostate and a mucus lake around the rectum. Fistulas of the prostatic and spongy portion of the urethra with bilateral scrotal abscess were also observed. After transverse colostomy and neoadjuvant chemotherapy with modified FOLFOX6 plus panitumumab, we performed total pelvic exenteration with genitalia resection. The entire surgical margin was tumor free, and the patient is alive with no evidence of recurrence. It is important to acquire an adequate surgical margin for locally advanced carcinoma associated with anal fistula, and combined-modality therapy and definition of the optimal extent of resection is necessary.
