Polyps in Lynch syndrome. Differences in quality of colonoscopy between Western and Eastern endoscopists
22 December 2014 (online)
Rondagh et al. published an interesting article in Endoscopy regarding nonpolypoid colorectal neoplasms in Lynch syndrome . In their study, the authors primarily focused on the differences in gross morphology of colonic neoplasms between different patient groups – those with and without Lynch syndrome.
Although, this well written, case-control, prospective study, with high quality statistical analysis, is interesting, the endoscopic evaluation of colorectal neoplasms could be further improved: incorporation of the new advanced endoscopic imaging techniques, such as indigo carmine chromoendoscopy, followed by magnification endoscopy in combination with narrow-band imaging (NBI) technology, could improve the real-time endoscopic diagnosis of colorectal neoplasms in Lynch syndrome.
Most endoscopists are well aware of Kudo’s pit pattern classification  , as well as the colonoscopic diagnosis of the nonpolypoid early colorectal cancer (CRC), described by Kudo in 2000  and the NBI magnifying classification  for endoscopic characterization of colorectal lesions; however, these characterization methods are rarely used in practice, as is the case in the abovementioned study .
We would like to propose the potential scientific importance of applying indigo carmine chromoendoscopy, followed by pit pattern analysis  and NBI magnifying classification  to patients with Lynch syndrome. As it is unproven whether there are differences in endoscopic characteristics of colorectal neoplasms between patients with and without Lynch syndrome, it is clearly an area that requires further study using these new endoscopic imaging techniques.
More precise characterization of lesions in Lynch syndrome with NBI magnification and Kudo’s pit pattern would be interesting in order to increase the endoscopic optical diagnosis of colorectal neoplasms in Lynch syndrome. In particular, these classifications are extremely important for endoscopic classification of lateral spreading tumors into granular and nongranular types, as the nongranular type has a higher risk of submucosal invasion, despite the benign nature of these lesions . NBI classification is particularly important in the evaluation of serrated adenomas (NBI classification type B) . Although serrated adenomas are, by definition, considered to be benign lesions, the sessile serrated type adenomas are related to dysplasia and cancer, and these challenging lesions should be better evaluated endoscopically in Lynch syndrome, mainly by NBI magnifying endoscopy.
Another potentially interesting issue that needs further investigation is the presence of depressed type (0-IIc) early CRC in Lynch syndrome, which can be better evaluated by NBI magnifying endoscopy . The existence of type 0-IIc colorectal neoplasms in the context of Lynch syndrome and the de novo CRC theory , might be an explanation for the increased occurrence of CRC in Lynch syndrome despite intensive colonoscopic surveillance  . However, further studies are necessary.
In conclusion, further study between patients with and without Lynch syndrome using Kudo’s pit pattern classification and NBI magnifying endoscopy could potentially result in enhancement of endoscopic tissue characterization of early colorectal neoplasms, and may reveal specific differences in endoscopic characteristics of nonpolypoid colorectal neoplasms in Lynch syndrome.
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