case_images: PMC9204206_01
case_images: Gastroscopy of acute erosive hemorrhagic gastritis for the first time (day 502). The esophageal mucosa was smooth with good contraction; the whole gastric mucosa was evidently edematous and hyperemic with opaque mucous adhesions on the surface. Diffuse erosion of white moss was seen, and active oozing of blood was extensively observed. The gastric antrum was found to have a necrotic mucosa with exfoliation of large flakes.
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case_images: A large amount of opaque white mucus was attached to the mucosal surface of the gastric antrum and body, and the gastric mucosa was diffusely hyperemic with spontaneous hemorrhage ( Supplementary Figure 1). The gastric antrum was found to have a necrotic mucosa with exfoliation of large flakes ( Figure 1 ).
case_images: Gastroscopy of acute erosive hemorrhagic gastritis after regular treatment (day 511). The esophageal mucosa was smooth with good contraction, and his EGD showed the whole gastric mucosa was hypermic and edematous, with diffuse erosion of white moss and active oozing of blood. Small flaps of mucosal necrosis and stripping could be seen at the posterior wall of the gastric antrum, which showed a relatively more healed condition than seen in the previous EGD.
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case_images: Then, he stopped the oral drug treatment without permission from the doctors after the symptoms subsided ( Supplementary Figure 2). Small flaps of mucosal necrosis and stripping could be visualized at the posterior wall of the gastric antrum, indicating a relatively healed mucosa compared with previous EGD findings ( Figure 2 ).
case_images: Pathologic findings of the biopsy specimen showed severe atrophic gastritis with erosion, atrophy, and loss of intrinsic glands; focal aggregation of lymphocytes in the lamina propria and mucosal muscular layer; multiple neutrophil infiltration; and the formation of small abscesses.
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case_images: Pathologic findings of the biopsy specimens from the gastric antrum showed severe atrophic gastritis with erosion, atrophy, and loss of intrinsic glands; focal aggregation of lymphocytes in the lamina propria and mucosal muscular layer; multiple neutrophil infiltration; and the formation of small abscesses ( Figure 3 ). We suspended sintilimab administration and simultaneously changed the regimen to steroid therapy as follows: intravenous methylprednisolone sodium succinate drip (100 mg, once daily for 4 days; 70 mg, once daily for 3 days; and 40 mg, once daily for 3 days), followed by oral methylprednisolone tablets as maintenance therapy (32 mg once daily for a week;  Supplementary    Figure 3 ).
case_images: Gastroscopy of acute erosive hemorrhagic gastritis after steriod treatment (day 526) showed marked improvements. The esophageal mucosa was smooth with good contraction. The whole gastric mucosa was hyperemic and edematous, with scattered flaky erosion (particularly in the gastric antrum) and partial bleeding. The gastric mucosa showed yellow-green bile and some white opaque mucus. Compared with the previous EGD findings, the mucosa as seen in this EGD was basically healed.
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case_images: Re-examination of EGD on day 526 showed markedly relieved edematous and hyperemic gastric mucosa and no signs of active oozing of blood compared to previous EGD findings ( Figure 4 ).