Colitis-Associated Dysplasia

White light imaging revealed endoscopic remission and a flat lesion with slightly reddish mucosa compared to the surrounding area in the rectum (Fig. a). Non-magnifying narrowband imaging (NBI) identified a brownish lesion (Fig. b). These findings create uncertainty with regard to diagnosing between inflammation and dysplasia. Switching to high-magnification NBI enhanced margin visibility (Fig. c), revealing small round surface structures in the brownish area. High-magnification chromoendoscopy using indigo carmine dye enhanced the visualization of the margin and surface of the lesion and identified a small round pattern in the reddish area, as well as mucosa displaying a gyrus pattern (upper left side of the lesion) and a ripple-like appearance (right side of the lesion) (Fig. d). Histological findings indicated high-grade dysplasia (HGD) in the biopsied specimen of the small round pattern; in contrast, no HGD was observed in the biopsied specimen of the ripple-like appear ance.