Fig. 1. Esophagogastroduodenoscopy (EGD). Case 1. EGD performed before initiation of vonoprazan treatment reveals an atrophic change in the antrum owing to past Helicobacter pylori infection, although no atrophic or mucosal changes are noted in the gastric body (A, B). EGD performed 1 and 2 years after initiation of vonoprazan treatment demonstrates newly appearing gastric cracked mucosa (GCM) (C–E) and multiple white spot (WS) and gastric polyps (GP) in the greater curvature of the lower gastric body on white-light imaging (WLI) (F), respectively. The GCM, WS, and GP observed on close-up WLI (G) are each highlighted as such on texture and color enhancement imaging mode 1 and narrow-band imaging (NBI) (H, I), respectively. Magnifying endoscopy with NBI indicates WS to be rich in microscopic vessels on the mucosal surface (J). Repeated EGD performed 1 year after switching from vonoprazan to esomeprazole demonstrates no change in GCM except for the disappearance of the WS and reduction of the GP size (K, L).

Fig. 2. Esophagogastroduodenoscopy (EGD). Case 2. EGD performed before initiation of vonoprazan treatment reveals a normal gastric mucosa with no atrophic or mucosal changes in the gastric body (A). EGD performed 2 years after vonoprazan initiation demonstrates newly appearing gastric cracked mucosa (GCM) and gastric polyps (GP) (B), and EGD performed 4 years later demonstrates enlarged GP and newly appearing multiple white spot (WS) in the greater curvature of the lower gastric body on white-light imaging (WLI) (C, D). The GCM and WS observed on close-up WLI (E) are highlighted on texture and color enhancement imaging mode 1 and narrow-band imaging (NBI) (F, G), respectively. Magnifying endoscopy with NBI indicates the WS to be rich in microscopic vessels on the mucosal surface (H). Repeat EGD performed 1 year after switching from vonoprazan to esomeprazole reveals no change in the GCM except for the disappearance of the WS and a slight decrease in the size of the GP (I, J).

Fig. 3. Pathological findings. A tissue biopsy from white spots reveals a mucus pool within a dilated duct, which tested positive for Alcian–periodic acid–Schiff staining. (A, B) Case 1, scale bar: 100 μm. (C, D) Case 2, scale bar: 500 μm.