A Case of Carcinoma Associated with Anal Fistula in Which Total Pelvic Exenteration was Performed after Neoadjuvant Chemoradiotherapy

We present herein a case of carcinoma associated with a long-term anal fistula, treated by total pelvic exenteration after neoadjuvant chemoradiotherapy. The 55-year-old male patient had a >30-year history of an intractable anal fistula, and had first been treated at 23-years-old. He was admitted to our hospital because of increasing anal pain with induration of the perianal region. A tumor was identified on the right side of the anus with a primary fistula and marked stenosis of the anus. An incisional biopsy was performed, revealing carcinoma associated with the anal fistula. Pelvic computed tomography and magnetic resonance imaging showed that the tumor occupied the entire circumference of the rectum, with marked invasion of the prostate. Neoadjuvant chemoradiotherapy was performed and tumor marker levels decreased greatly. Pelvic exenteration was performed with reconstruction of a neobladder using a small intestinal pouch, and the defect of the pelvic floor and perianal skin was repaired using a rectus abdominus pedicle flap. Histopathologically, no viable cancer cell was existence on surgical margin due to the necrotic and degenerative changes of cancer cell followed by neoadjuvant chemoradiotherapy. As of 3 months later, tumor markers again increased and lymph-node swelling in the right inguinal region was detected. Chemotherapy has thus been initiated. Neoadjuvant chemoradiotherapy was considered effective for locally advanced carcinoma associated with anal fistula, as no evidence of local recurrence has been observed in this series.