3052 Colonic Polyp Found on Capsule Endoscopy After a Normal Colonoscopy: A Case Report and Literature Review

Abstract

INTRODUCTION: Video capsule endoscopy (VCE) is a vital diagnostic tool in detecting occult gastrointestinal bleeding but has limited use in detecting colonic polyps due to low sensitivity and specificity. We present a case of a missed colonic polyp by colonoscopy that was detected with capsule endoscopy. CASE DESCRIPTION/METHODS: A 50-year-old man with an extensive cardiac history on systemic anticoagulation presented with symptomatic anemia, intermittent melena, and labs consistent with blood loss anemia. He underwent an endoscopy and colonoscopy in July 2018 and a push enteroscopy in February 2019 due to persistent symptoms, which were all normal and did not identify the etiology of obscure GI blood loss. Given the unresolved symptomatic anemia, the patient underwent VCE that did not identify any etiologies of small bowel bleeding, however, it did show a medium to large sized sessile polyp in the colon that not appreciated on colonoscopy eight months earlier. DISCUSSION: A head to head comparison of colonoscopy and VCE has shown that VCE's sensitivity and specificity for detecting adenomas 6 mm or larger are 64% and 84%, respectively. In fair or poorly prepped colons, VCE sensitivity and specificity for detecting adenomas 6 mm or larger dropped to 44% and 81%, making VCE an inferior choice for colon polyp detection. While colonoscopy remains the gold standard for colorectal cancer surveillance, the potential for missed polyps exists. In a recent tandem study with same-day consecutive colonoscopies, the adenoma miss rate was 24.1%. However, advanced adenomas and carcinoma miss rate was lower and significantly dropped to 1.2% and 0%, respectively. Right-sided, sessile, small adenomas were more likely to be missed than left-sided, pedunculated, large adenomas. Additionally, findings greater than two polyps were also associated with an increased missed rate. Current proposed methods for increasing adenoma detection rate include increased withdrawal time, multiple observers, and enhanced imaging modalities such as narrow band imaging. In this case, VCE identified a polyp not seen on colonoscopy from eight months prior. Although VCE currently does not meet the standards of a colorectal cancer screening, VCE's minimally invasive nature, lack of sedation and patient preference warrants continued work to define its role in the cancer-screening algorithm.