Case 1 was a 55-year-old man who underwent a fistulectomy for vesicorectal fistula in 1989, at which time CD was diagnosed. He attended our hospital for the first time in August 2002 and was treated on an inpatient basis with an elemental diet

and mesalazine. He attended our hospital in March 2003 complaining of an increase in pain in the anal region. Colonoscopy was not performed because of anal stenosis, and severe lower rectal stenosis was confirmed by barium enema (Fig. 1). We performed blind biopsy by inserting forceps into rectum in April. Adenocarcinoma was diagnosed histologically, and in May he underwent abdominoperineal resection under a diagnosis of rectal cancer (Fig. 2). Adenocarcinoma cells were found to have slightly infiltrated the anal sphincter, but GSK-3 activation the resection stump margin was negative (Fig. 3). Metastasis to the lung was found in August 2004, and chemotherapy with UFT + leucovorin was started. The regimen was changed to FOLFOX in March 2006, but local recurrence in the pelvis was noted in August 2007, and he died in April 2009. Case 2 was a 37-year-old man who was diagnosed with ileocolitis-type PF-6463922 concentration CD in March 1992. He attended our hospital for the first time in 1998 and was treated with an elemental diet, mesalazine, prednisolone, and azathioprine. Double balloon

endoscopy was performed approximately every 2 years, and stenosis of the ileum and an inflammatory polyp in the terminal ileum were noted in August 2008. He was hospitalized for an exacerbation of abdominal pain on 21 December 2009. Ileus developed on 29 December and an ileus tube was inserted (Fig. 4), but without improvement. He therefore underwent jejunum resection and jejunostomy on 5 January 2010. The perioperative finding MCE was a large number of miliary nodes in the abdominal cavity (Figs 5,6). An adenocarcinoma was found in the serosa of resected specimen

(Fig. 7). Positron emission tomography/computed tomography (PET/CT) was performed after the operation, and the accumulation of 18F-fluorodeoxyglucose (FDG) was not found besides small bowel. He was diagnosed with peritoneal dissemination of small intestinal cancer. As of May 2011, he continues to receive postoperative chemotherapy. Warren and Sommers reported the first case of CRC as a complication of CD in 1948,10 and Ide et al. reported the first case in Japan in 1971.11 Regarding site, the majority of cases of CRC complicating CD in Europe and America are reported on the right side,12 compared with on the left in Japan (right side 15, left side 66). Rectal/anal cancer was the most common, accounting for 51 cases (63%), and many cases showed a long-term course in which cancer occurred more than 10 years after the onset of CD (55%), although many cases were diagnosed at the same time as CD (25%). Regarding the time of diagnosis, 60% of cases were definitively diagnosed by preoperative biopsy, and 25% were diagnosed postoperatively.