Characteristic magnifying narrow-band imaging features of colorectal tumors in each growth type

Abstract

We investigated the surface characteristics and vascular patterns of colorectal tumors according to growth type by means of magnifying narrow-band imaging (NBI). Four hundred ninety-seven colorectal tumors larger than 10 mm (204 tubular adenomas [TAs], 199 frankly invasive intramucosal carcinomas to shallow invasive submucosal [M/SM-s] carcinomas, and 94 deeply invasive submucosal [SM-d] carcinomas) were analyzed. These colorectal tumors were classified according to growth type as follows: polypoid type, n = 224; laterally spreading tumor-granular (LST-G) type, n = 133; and LST-non-granular (LST-NG) type, n = 140. Surface and vascular patterns were evaluated in relation to histology and growth type. The absent and irregular surface patterns were observed in approximately 40 % of the SM-d carcinomas of the polypoid and LST-G type. The unclear surface pattern was more frequent in tumors of the LST-NG type than in those of other growth types, regardless of histology. Among TAs and M/SM-s carcinomas, the dense vascular pattern was most frequent in polypoid type, the dense and corkscrew vascular patterns were most frequent in the LST-G type, and the honeycomb and avascular and/or fragmentary patterns were most frequent in the LST-NG type. The avascular and/or fragmentary vessel pattern was more frequent in SM-d carcinomas than in TA and M/SM-s carcinomas, regardless of growth type. A part of LST-NG was difficult to identify the NBI magnifying surface pattern. Although NBI magnifying findings were almost same in each type lesion in SM-d lesion, those of LST-NG were different from those of LST-G and polypoid type in M/SM-s lesion.