Purpose: We report four cases of Crohn's disease (CD)-associated colorectal cancer (CRC) in our department. CASE 1: A 42-year-old Japanese man had a 14-year history of ileocolon CD. He had a history of an ileocecal resection and a stricture plasty. At the age of 42, sigmoid colostomy was performed because of the deterioration of the anal stenosis. After this operation, the perianal pain had remained, and a magnetic resonance imaging scan revealed a rectal tumor. CASE 2: A 30-year-old Japanese man had a 13-year history of ileocolon CD. He had a history of an ileostomy, a subtotal colectomy, and ileo-rectal anastomosis. At the age of 30, he had perianal pain, and a colonoscopy revealed a rectal cancer. An abdomino-perineal resection of the remnant rectum was performed. CASE 3: A 46-year-old Japanese man had a 9-year history of ileocolon CD. He experienced abdominal fullness. Colonoscopy revealed an ascending colon cancer. He underwent a subtotal colectomy and ileo-rectal anastomosis. CASE 4: A 33-year-old Japanese woman had a 16-year history of ileocolon CD. She had no changes in symptoms of CD. Surveillance colonoscopy revealed a transverse colon cancer. She underwent a subtotal colectomy and ileo-rectal anastomosis.
Conclusion: As the number of patients with CD and with CD-associated CRC has increased in Japan, CD-associated CRC, as noted in these patients, should be kept in mind in the management of patients with CD. In addition, a surveillance system of patients with CD should be established and should prompt further study about CD-associated CRC.