[Colorectal Cancer Associated with Crohn's Disease-A Case Report].

We report a case of colorectal cancer associated with Crohn's disease in a 50-year-old man. He had been diagnosed with Crohn's disease 26 years before and had undergone sigmoidectomy for sigmoid colon stenosis 19 years before. Ileal resection, was performed for ileus stenosis 12 years before. Three years before, partial resection of the small intestine was performed for perforation of the small intestine. During this period, the medical treatment was continued, but the patient experienced remission and exacerbation. He complained of anal pain at a regular outpatient visit, and endoscopic examination showed an elevated lesion immediately above the dentate line. Adenocarcinoma Group 5 was detected on biopsy. The diagnosis was rectal cancer(cT2N3M0, StageⅢb). We performed an abdominoperineal resection, a D3 lymph node dissection, and colostomy. Chemotherapy with mFOLFOX6 was provided postoperatively. The patient has survived without recurrence for 1 year and 6 months after the surgery.