New-generation endocytoscopy with CM double staining for optical characterization of colon sessile serrated adenoma

New-generation endocytoscopy (single lens, continuous zoom) enables in vivo ultra-high magnification (520 ×) for visualization at the cellular level and allows a precise pathological prediction of gastrointestinal (GI) neoplasia [1].

A 60-year-old man received colonoscopy screening owing to a positive fecal immunochemical test. A 1.2-cm slightly whitish colon polyp was found at the sigmoid colon by white imaging and narrow-band imaging ([Fig. 1]). Endocytoscopy (CF-H290ECI endocytoscope; Olympus, Tokyo, Japan) was performed after CM double staining (0.05 % crystal violet and 1 % methylene blue mixture) ([Fig. 2], [Video 1]). It showed dilated gland lumens, i. e., oval crypt openings with some small round nuclei ([Fig. 3]) [2] [3] [4]. Polypectomy was done, and the histology revealed typical features of sessile serrated adenoma, with dilated and L-shaped crypts ([Fig. 4]) [5]. Sessile serrated adenomas are precursors of colorectal cancers and must be distinguished from hyperplastic polyps and treated endoscopically. Endocytoscopy is a promising tool for optical characterization of sessile serrated adenoma to guide subsequent endoscopic management.

Fig. 1 A colon polyp was detected at the sigmoid colon. a White-light image. b Narrow-band image.

Fig. 2 Prior to endocytoscopic observation, a mixture of 0.05 % crystal violet and 1 % methylene blue was prepared to stain the cytoplasm and nucleus, respectively.

Video 1 Endocytoscopy with CM double staining (crystal violet and methylene blue) to characterize the colon sessile serrated adenoma, demonstrating dilated oval crypt openings with some small round nuclei.

Fig. 3 Endocytoscopy for characterization of sessile serrated adenoma demonstrated dilated crypt openings with some small round nuclei.

Fig. 4 The pathological analysis of the polyp showed dilated and L-shaped crypts, which are compatible with the diagnosis of sessile serrated adenoma.

Endoscopy_UCTN_Code_CCL_1AD_2AB

• References

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• 5 Rosty C, Hewett DG, Brown IS. et al. Serrated polyps of the large intestine: current understanding of diagnosis, pathogenesis, and clinical management. J Gastroenterol 2013; 48: 287-302