Diagnosis of undifferentiated type early gastric cancers by magnification endoscopy with narrow-band imaging

Background and Aims: The diagnostic use of magnification endoscopy with narrow-band imaging (ME-NBI) to assess histopathologically undifferentiated-type early gastric cancers (UD-type EGCs) is not well elucidated. The purpose of this study was to examine the comparative relationship between ME-NBI images and histopathological findings in UD-type EGCs. Methods: We analyzed 78 consecutive cases of UD-type EGCs <= 20 mm in diameter that underwent ME-NBI <= 2 weeks prior to resection. The ME-NBI images were compared with histopathological findings following either endoscopic submucosal dissection (ESD) or surgery. Applying the comparative results, we prospectively evaluated the success of identifying the lateral extent of UD-type EGCs resected by ESD in additional consecutive cases. Results: Lesions with preserved but irregular surface microstructures (S-type based on ME-NBI) showed mucosal atrophy and corresponded histologically to the non-whole-layer type of intramucosal cancer (24/24, 100%). Lesions with an irregular microvasculature type (V-type, for example, corkscrew pattern) or mixed type upon ME-NBI corresponded histopathologically to the non-whole-layer type of intramucosal cancer (15/54, 27.8%), the whole-layer type of intramucosal cancer (27/54, 50.0%) or submucosal (sm) invasion cancer (12/54, 22.2%). Applying these comparative results, we used ME-NBI to successfully predict the lateral extent of cancer, which corresponded to the histopathological lateral extent in all 18 additional consecutive UD-type EGCs resected by ESD. Conclusions: ME-NBI images of UD-type EGCs were very closely related to the histopathological findings. Thus, ME-NBI can be useful in the pretreatment assessment of the histopathological patterns of cancer development and the lateral extent of such lesions.