Watery Diarrhea in a Patient With Metastatic Appendiceal Adenocarcinoma

Abstract

A 72-year-old man with recently diagnosed metastatic appendiceal adenocarcinoma undergoing chemotherapy with capecitabine plus oxaliplatin presented with lower abdominal pain and watery, large-volume diarrhea up to 15 times per day for the previous 3 weeks. His diarrhea was nonbloody, woke him up from sleep, was accompanied by crampy abdominal pain, and was not associated with nausea or vomiting. The diarrhea persisted despite treatment with combinations of loperamide, atropine/diphenoxylate, colestipol, and tincture of opium. He required repeated intravenous infusions for fluid and electrolyte repletion. His physical examination results revealed normal vital signs and a mildly tender abdomen with hyperactive bowel sounds, but no peritoneal signs. His laboratory workup results were notable for severe hypokalemia and hypomagnesemia, as well as positive fecal lactoferrin and elevated fecal calprotectin levels of 646 μg/g. His infectious workup results were unremarkable. A computed tomography scan of the abdomen/pelvis revealed diffuse longsegment wall thickening involving nearly the entire terminal ileum (Figure , A). An ileocolonoscopy revealed erythematous and congested mucosa with scattered erosions and ulcerations throughout the examined terminal ileum (Figure , B). Targeted biopsies were obtained (Figure , C). Histopathology C Colonoscopy B Contrasted computed tomography A Figure. Contrasted computed tomography of the abdomen and pelvis (A), colonoscopy (B), and histopathology (hematoxylin-eosin, original magnification ×100) (C). WHAT IS YOUR DIAGNOSIS? A. Cytomegalovirus ileitis B. Capecitabine-induced terminal ileitis C. Ileal metastasis D. Small bowel carcinoid tumor Clinical Review & Education