Disagreement between high confidence endoscopic adenoma prediction and histopathological diagnosis in colonic lesions ≤ 3 mm in size
submitted 29. Mai 2018
accepted after revision 03. Januar 2019
05. Februar 2019 (eFirst)
Background Diminutive colorectal polyps resected during colonoscopy are sometimes histologically interpreted as normal tissue. The aim of this observational study was to explore whether errors in specimen handling or processing account in part for polyps ≤ 3 mm in size being interpreted as normal tissue by pathology when they were considered high confidence adenomas by an experienced endoscopist at colonoscopy.
Methods One endoscopist photographed 900 consecutive colorectal lesions that were ≤ 3 mm in size and considered endoscopically to be high confidence conventional adenomas. The photographs were reviewed blindly to eliminate poor quality images. The remaining 644 endoscopy images were reviewed by two external experts who predicted the histology while blinded to the pathology results.
Results Of 644 consecutive lesions ≤ 3 mm in size considered high confidence conventional adenomas by a single experienced colonoscopist, 15.4 % were reported as normal mucosa by pathology. The prevalence of reports of normal mucosa in polyps removed by cold snare and cold forceps were 15.2 % and 16.0 %, respectively. When endoscopy photographs were reviewed by two blinded outside experts, the lesions found pathologically to be adenomas and normal mucosa were interpreted as high confidence adenomas by endoscopic appearance in 96.9 % and 93.9 %, respectively, by Expert 1 (P = 0.15), and in 99.6 % and 100 %, respectively, by Expert 2 (P = 0.51).
Conclusion Retrieval and/or processing of tissue specimens of tiny colorectal polyps resulted in some lesions being diagnosed as normal tissue by pathology despite being considered endoscopically to be high confidence adenomas. These findings suggest that pathology interpretation is not a gold standard for lesion management when this phenomenon is observed.
- 1 Rex DK, Alikhan M, Cummings O. et al. Accuracy of pathologic interpretation of colorectal polyps by general pathologists in community practice. Gastrointest Endosc 1999; 50: 468-474
- 2 Lasisi F, Mouchli A, Riddell R. et al. Agreement in interpreting villous elements and dysplasia in adenomas less than one centimetre in size. Dig Liver Dis 2013; 45: 1049-1055
- 3 Khalid O, Radaideh S, Cummings OW. et al. Reinterpretation of histology of proximal colon polyps called hyperplastic in 2001. World J Gastroenterol 2009; 15: 3767-3770
- 4 Rex DK, Hassan C, Bourke MJ. The colonoscopist’s guide to the vocabulary of colorectal neoplasia: histology, morphology, and management. Gastrointest Endosc 2017; 86: 253-263
- 5 Rex DK. Narrow-band imaging without optical magnification for histologic analysis of colorectal polyps. Gastroenterology 2009; 136: 1174-1181
- 6 Kaltenbach T, Rastogi A, Rouse RV. et al. Real-time optical diagnosis for diminutive colorectal polyps using narrow-band imaging: the VALID randomised clinical trial. Gut 2015; 64: 1569-1577
- 7 Hewett DG, Kaltenbach T, Sano Y. et al. Validation of a simple classification system for endoscopic diagnosis of small colorectal polyps using narrow-band imaging. Gastroenterology 2012; 143: 599-607
- 8 Barge W, Kumar D, Giusto D. et al. Alternative approaches to polyp extraction in colonoscopy: a proof of principle study. Gastrointest Endosc 2018; 88: 536-541
- 9 Rex DK, Ponugoti P, Kahi C. The “valley sign” in small and diminutive adenomas: prevalence, interobserver agreement, and validation as an adenoma marker. Gastrointest Endosc 2017; 85: 614-621
- 10 Johnson DA, Barkun AN, Cohen LB. et al. Optimizing adequacy of bowel cleansing for colonoscopy: recommendations from the U.S. Multi-Society Task Force on Colorectal Cancer. Gastrointest Endosc 2014; 80: 543-562
- 11 Lieberman DA, Rex DK, Winawer SJ. et al. Guidelines for colonoscopy surveillance after screening and polypectomy: a consensus update by the US Multi-Society Task Force on Colorectal Cancer. Gastroenterology 2012; 143: 844-857
- 12 van Rijn JC, Reitsma JB, Stoker J. et al. Polyp miss rate determined by tandem colonoscopy: a systematic review. Am J Gastroenterol 2006; 101: 343-350
- 13 Rex DK, Schoenfeld PS, Cohen J. et al. Quality indicators for colonoscopy. Gastrointest Endosc 2015; 81: 31-53
- 14 Kessler WR, Imperiale TF, Klein RW. et al. A quantitative assessment of the risks and cost savings of forgoing histologic examination of diminutive polyps. Endoscopy 2011; 43: 683-691