P019 Not All Fecal Calprotectin is Specific for Inflammatory Bowel Disease

Introduction:Fecal calprotectin is a known inflammatory marker used to evaluate patients with Inflammatory Bowel Disease (IBD). In fact, ACG Clinical Guideline for management of Crohn's disease recommend fecal calprotectin (FC) as a helpful test to distinguish IBD versus functional disorder such as Irritable Bowel Syndrome. Studies have also shown association of fecal calprotectin with colon cancer. Recent study proposed fecal calprotectin could be a reliable marker for ruling out organic disease with high negative predictive value.

We present a patient case of a Caucasian, thirty-five years of age male with PMHx of GERD on Prilosec who presented due to acute abdominal pain, nausea, emesis and watery, nonbloody diarrhea of four days duration. Initially, patient had unknown family history of colon cancer which later was revealed that patient's father had a colon cancer diagnosis in his fifties. On admission, patient had stable vitals with routine labs showing leukocytosis, iron deficiency anemia, normal CRP, and elevated fecal calprotectin of 986mcg/gm. Abdominal imaging with CT abdomen with contrast showed diffuse dilation of ileum and thickening of the distal ileum up to the level of the ileocecal junction, suggestive of enteritis from infectious or inflammatory etiology such as Crohn's. Patient was managed conservatively, stool studies were negative otherwise and discharged with outpatient endoscopy due to high suspicion for Inflammatory Bowel Disease. Within one week, patient had a subsequent readmission for now partial small bowel obstruction at the level of ileum. Due to high suspicion of Crohn's, patient was empirically started on IV steroids. Decision for inpatient colonoscopy was made with colonoscopy showing completely obstructing, circumferential, large mass found in the cecum extending into ascending colon. Final pathology revealed invasive mucinous adenocarcinoma, moderately differentiated. Patient subsequently underwent right hemicolectomy with lymph node resection and adjuvant chemotherapy treatment for stage 3 colon.

We present here a case where a common cancer was found in an otherwise healthy, young male with acute abdominal pain and altered bowel habits. While initial symptoms, imaging and laboratory findings pointed towards a biased high suspicion for Inflammatory Bowel Disease, patient's ultimate diagnosis was stage 3 adenocarcinoma of colon requiring surgical resection and chemotherapy. Fecal calprotectin is a known marker for colon inflammation and associated with both IBD and colon cancer. It is important to keep in mind that while fecal calprotectin may have elevated negative predictive value and be used to rule out organic disease, elevation of fecal calprotectin is not always specific for IBD. We want to emphasize the importance of considering colon cancer on the differential despite a patient's age and diagnostic bias. Lastly, we also want to highlight the importance of tissue diagnosis prior to long term therapy use.