Evaluation of narrow band imaging findings in discolored depressed gastric lesions

Objective : The purpose of this study was : (1) to observe, via narrow band imaging (NBI) magnifying endoscopy, discolored depressed lesions, in which the differential diagnosis included gastric adenoma and well-differentiated adenocarcinoma, and which were classified as Group HI by biopsy ; (2) to characterize them by their endoscopic appearance ; and (3) to evaluate the usefulness of our previously reported system (which is useful for the diagnosis of IIa-like gastric lesions) for the classification of these lesions by type. Methods : Nine discolored depressed lesions, classified as Group III by biopsy, were studied in patients who had undergone conventional endoscopy and NBI magnifying endoscopy in our department during the 16 months between November 2008 and February 2010. These lesions were observed with NBI magnifying endoscopy, classified according to our proposed system of type classification, and compared with the results of the pathological examination of the resected specimens and with 59 discolored, flat-elevated lesions (classified as Group III by biopsy) that had been observed during the same period. Results : Pathological examination of all nine resected specimens led to a diagnosis of well-differentiated adenocarcinoma. Based on NBI magnification findings, 0, 0, 2, 3, and 4 lesions were classified as Type I, II, III, IIIs, and IV, respectively. The discolored depressed lesions resembled elevated lesions with a depression, such as type IIa + IIc, with respect to NBI findings, pathological features, and the site of the lesion. Conclusion : These results suggest that our proposed system of type classification is also useful for the differential diagnosis of benign vs. malignant, discolored, depressed lesions.