ABSTRACT
Crohn's disease is a chronic inflammatory disease that can involve the entire gastrointestinal tract. Several studies indicate that Crohn's patients with long disease duration have an increased risk of small bowel or colorectal cancer. In Korea, only a few cases of Crohn's disease-related small bowel or colorectal cancer have been reported. Here, we described 3 cases of colorectal cancer and 2 cases of small bowel cancer in patients with Crohn's disease. Among 5 patients, 3 had Crohn's disease-related lower gastrointestinal malignancy and the other 2 had sporadic lower gastrointestinal malignancies. Since the diagnosis of Crohn's disease-related lower gastrointestinal malignancy tends to be delayed, the development of malignancy should be considered in patients with long duration of Crohn's disease if patients have refractory symptoms despite intensive medical treatment. Surgical consultation should not be delayed.