2522 An Unusual Case of a Colo-enteric Fistula

Abstract

INTRODUCTION: Entero-enteric fistulas are complications seen in patients with active Crohn's disease or history of extensive intra-abdominal surgeries. Presentations can be non-specific and include disease progression, rectal bleeding, or persistent febrile episodes. Upper and lower gastrointestinal endoscopy are used to diagnose entero-enteric fistulas. Contrast injection along with abdominal radiography can visualize and provide further anatomical details. In the following report, we present the case of a patient with pancreatic adenocarcinoma who presented with rectal bleeding. The diagnosis of colo-enteric fistula was made by fluoroscopy with contrast injection and pathology results. CASE DESCRIPTION/METHODS: A 62-year-old male with PMH of pancreatic adenocarcinoma treated with chemotherapy and whipple procedure complicated by multiple recurrences of liver metastases treated with radiofrequency ablation and excision of abdominal wall implants, who presented with rectal bleeding. On admission, EGD did not identify the source of bleeding, Colonoscopy showed a 4 cm ulcerated pocket at the hepatic flexure. Contrast injected into the pocket revealed a fistulous tract with an extra-colonic segment. Traversing the tract with the colonoscope revealed small bowel tissue. Biopsies of fistulous opening was consistent with necrotic tissue concerning for metastatic implants. DISCUSSION: To the best of our knowledge, most entero-enteric are caused by either active untreated Crohn's disease or as a result of multiple abdominal surgeries. This is a rare case of colo-enteric fistula formation due to metastatic pancreatic cancer. Few case reports show intra-colonic fistula formation due malignancy. Upon literature review, there are case reports of primary lymphoma leading to colo-enteric fistula formation. Diagnosis was difficult to achieve due to non-specific clinical presentation of chronic diarrhea. The fistula was diagnosed by computed tomography enterography (CTE) demonstrated a ileo-ileal fistula and ileo-colonic fistula. Ultrasound (US) showed small intestinal wall thickening and development of a fistula of the sigmoid colon due to malignancy. Although rare, enteric fistula formation due to malignancy should be suspected in patients with GI symptoms and history of metastatic disease.