Case Atlas and Illustrations of Early GI Cancers: Colon

Abstract

The endoscopic diagnosis of early colorectal neoplasia can be improved by using narrow-band imaging (NBI). Recently, the NBI International Colorectal Endoscopic (NICE) classification has been validated for the diagnosis of colorectal lesions using non-magnifying endoscopy. In addition, Workgroup serrAted polypS and Polyposis (WASP) classification was recommended for optical diagnosis of sessile serrated lesions. This chapter will demonstrate the examples of optical diagnosis of colorectal neoplasia using non-magnifying endoscopy with NBI.

The NICE type 1 polyps are most likely nonneoplastic. The color of polyps is similar to or lighter than the background; there is no blood vessels or only isolated lacy vessels on the surface. The surface may show uniform dark spots (Fig. 18.1), white spots (Fig. 18.2), or absence of surface pattern [1] (Fig. 18.3).

Fig. 18.1

Hyperplastic polyp with uniform dark spots

Fig. 18.2

Hyperplastic polyp with uniform white spots

Fig. 18.3

Hyperplastic polyp with absence of surface pattern

The NICE type 2 polyps are most likely intramucosal neoplasia. Their color is darker than the background. There are brown blood vessels surrounding white structures which represent pit pattern. These surface pit pattern may be oval (Fig. 18.4), tubular (Fig. 18.5), or branched pattern [1] (Fig. 18.6).

Fig. 18.4

Tubular adenoma with oval surface pattern

Fig. 18.5

Tubular adenoma with tubular surface pattern

Fig. 18.6

Tubular adenoma with branched surface pattern

The NICE type 3 polyps are most likely invasive cancer. In this group, the color is darker than the background. Moreover, they have area of disrupted blood vessels and the surface pattern are absent [1] (Fig. 18.7).

Fig. 18.7

Colonic carcinoma

However, the NICE classification has limitations for differentiation of sessile serrated polyps [2] which are also the precursor lesions of colorectal cancer. The “Workgroup serrAted polypS and Polyposis” (WASP) classification combines four features, namely, cloud-like surface, indistinct border, irregular shape, and dark spots inside the crypts into the NICE classification and the polyps with at least two features should be considered sessile serrated lesions [3] (Figs. 18.8 and 18.9). The mucus cap is a common feature of sessile serrated lesions as well [4] (Fig. 18.10). Some of the sessile serrated lesions may have NICE classification type 1 (Figs. 18.11 and 18.12) while the others may have NICE classification type 2 [3] (Figs. 18.13 and 18.14).

Fig. 18.8

Sessile serrated lesion with white light imaging

Fig. 18.9

Sessile serrated lesion with cloud-like surface, indistinct border, irregular shape, and dark spots inside the crypts

Fig. 18.10

Sessile serrated lesion with mucus cap

Fig. 18.11

Sessile serrated lesion

Fig. 18.12

Sessile serrated lesion with NICE 1 pattern

Fig. 18.13

Sessile serrated lesion with white light imaging

Fig. 18.14

Sessile serrated lesion with NICE 2 pattern