Histologic discrepancy between endoscopic forceps biopsy and endoscopic mucosal resection specimens of colorectal polyp in actual clinical practice

ABSTRACT

BACKGROUND/AIMS: We aimed to assess the rate of histologic discrepancy (HD) between endoscopic forceps biopsy (EFB) and totally resected specimens in colorectal polyp and analyze the risk factors of discordant group, especially under-diagnosis (UD) cases before complete removal of colorectal polyp. METHODS: From 2010 to 2015, a total of 290 polyps in 210 patients which had baseline pathology report before endoscopic resection (ER) were analyzed. UD cases were defined as those in which the diagnosis changed to a more advanced histologic feature after ER. RESULTS: A change in the final histology after ER was noted in 137 cases (47.2%), and after excluding 9 insignificant cases, 128 cases were further categorized into over-diagnosed and under-diagnosed group. UD occurred in 86 cases (29.7%) and change from benign to malignancy was noted in 26 cases (8.9%). On univariate analysis, a larger polyp size (>10 mm) was significantly associated with both HD (P 10 mm was the single most significant predictor of both HD (P 10 mm was the most important predictor of both HD and UD. We should be careful in making treatment strategy of colorectal polyp based on histologic report of EFB especially when the size of polyp is >10 mm.