Work

Light blue crest sign visualized by magnifying endoscopy in normal colonic mucosa

Year: 2021

Type: article

Abstract: Light blue crest (LBC), defined as a fine, blue-white line on the crests of the epithelial surface/gyri, is always discerned at the edge of marginal crypt epithelium [ 1 ]. The optical sign has high specificity for the endoscopic identification of gastric intestinal metaplasia [ 1 ]. It can only be visualized by magnifying endoscopy with narrow-band imaging or blue-laser imaging, and is caused by the reflectance of short-wavelength light (400–430 nm) on the microvillous surface of the epithelium [ 1 ] [ 2 ]. LBC is naturally seen in normal small intestine due to regular microvilli arrangement [ 1 ]. Herein, we describe the LBC sign in normal colonic mucosa. Colonic screening (GIF-H290Z; Olympus, Tokyo, Japan) was performed in a 40-year-old healthy man. When the colonic mucosa was fully dilated, the LBC sign could hardly be found. However, when the colon was partially collapsed and innominate grooves reappeared, creating a finely nodular surface, long linear LBCs could be seen in the corresponding grooves ([ Fig. 1 a, ] [ Video 1 ]) or in tangential view of the colonic mucosa ([ Fig. 1 b ]). Dot- or rod-like LBCs could also be found in partial crypt openings ([ Fig. 1 c ]). Fig. 1 Normal colonic mucosa by magnifying endoscopy and narrow-band imaging. a The colon was partially collapsed and innominate grooves reappeared. Light blue crest (LBC) signs could be seen in the innominate grooves and crypt openings. b The long, linear, LBCs could be seen in tangential view of colonic mucosa (arrowheads). c Dot- or rod-like LBCs could be seen in partial crypt openings. Video 1 Light blue crest (LBC) sign is naturally seen at the edge of the villi in normal duodenum. Innominate grooves reappear in the colon following partial collapse. Linear, dot- or rod-like LBCs can be seen clearly in innominate grooves and crypt openings. Quality: mobile 360 480 720 Download Numerous crypts of Lieberkühn and innominate grooves were observed on the surface of colonic mucosa by scanning electron microscopy [ 3 ]. Examination by light microscopy of sections treated with hematoxylin and eosin and with immunohistochemical stains revealed that several crypts of Lieberkühn opened into innominate grooves ([ Fig. 2 ]) [ 3 ]. Innominate grooves and the upper part of Lieberkühn crypts were lined by mature absorptive cells [ 3 ], which possessed closely packed regular microvilli [ 4 ]. In tangential view of colonic mucosa (namely, perpendicular view of microvillous longitudinal axis), LBCs can be obtained by magnifying endoscopy, with regular microvilli illuminated by narrow-band blue light. No LBCs can be seen in normal gastric mucosa due to the lack of regular microvilli in foveolar epithelium [ 5 ]. Fig. 2 Histological examination. a Hematoxylin and eosin staining revealed several crypts of Lieberkühn opening into innominate grooves (arrow) (× 100; bar 200 μm). b Villin immunohistochemical staining. Villin is a structural protein of microvilli. Positive areas represent the distribution of microvilli on the surface of colonic epithelial cells in innominate groves (arrow), crypts (arrowhead), and between crypts (× 100; bar 200 μm). Endoscopy_UCTN_Code_CCL_1AD_2AJ Endoscopy E-Videos https://eref.thieme.de/e-videos Endoscopy E-Videos is a free access online section, reporting on interesting cases and new techniques in gastroenterological endoscopy. All papers include a high quality video and all contributions are freely accessible online. This section has its own submission website at https://mc.manuscriptcentral.com/e-videos Publication History Publication Date: 08 October 2021 (online) © 2021. Thieme. All rights reserved. Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, Germany

Source: Endoscopy

DOI: 10.1055/a-1625-4859