Colon Adenocarcinoma Metastasis Through Ileocolic Fistula to Small Bowel in the Setting of Crohn’s Disease

Abstract Purpose: Patients with Crohn’s disease (CD) are at higher risk of developing colorectal cancer (CRC) and gastrointestinal fistula. We report an unusual case of sigmoid colon adenocarcinoma in a CD patient that metastasized to the small bowel through an ileocolic fistula tract.Methods: This case report was written after patient was seen in the clinic and reviewing overall hospitalization including clinically relevant data including imaging and pathology reports associated to our focus and presentation. Prior cases of metastatic CRC via fistula tract were reviewed and compared as well. Results: We described an unprecedented case of a sigmoid adenocarcinoma metastasized to ileum via ileal-sigmoid fistula. Patient received surgical treatment and systemic chemotherapy and currently in remission. Conclusion: CD is associated with a higher risk of fistula development. Few cases in the past described CRC metastasized within the gastrointestinal tract through a fistula. Intriguingly in our case, sigmoid adenocarcinoma developed and further metastasized to the ileum via the ileal-sigmoid fistula in the setting of CD. In addition to presenting a unique pathological phenomenon in these patients, this case raises awareness of the importance of regular follow-up and early initiation of IBD therapies.