case_images: PMC10718579_01
case_images: Endoscopic findings. Slightly elevated lesions both on the anterior wall (arrows (a)) and lesser curvature (arrows (b)) were endoscopically observed in the upper part of the stomach.
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case_images: PMC10718579_01_cro-2023-0016-0001-533363_F01.jpg
case_images: F1
case_images: Diagnostic upper gastrointestinal endoscopy showed slightly elevated two lesions both on the anterior wall and lesser curvature in the upper part of the stomach (Fig. 1).
case_images: Computed tomography (CT) of the stomach. Oval cyst-like lesions were observed in the gastric wall (arrows) without any extra-gastric lesions.
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case_images: PMC10718579_01_cro-2023-0016-0001-533363_F02.jpg
case_images: F2
case_images: We had noticed cyst-like lesions in the gastric wall on computed tomography (CT) but had regarded them not to be correlated with the presumed early gastric cancers before ESD (Fig. 2).
case_images: Pathological findings. a Probably due to the ESD, no macroscopic elevated lesions were observed on the gastric luminal surface. A protruded lesion toward the serosa (arrows) and cyst-like lesions (asterisks) were observed in the gastric wall. b The externally protruded lesion (arrows) was composed of well-differentiated atypical cells spreading out the gastric wall. c Magnified view of the central part of the protruded lesion showed atypical cells growing in a papillary fashion (arrows). d Magnified view of the mucosal part of the lesion showed atypical cells growing in a tubular fashion, i.e., a less differentiated form than a papillary growth form (asterisk). e Magnified view of the subserosal part of the lesion showed atypical cells with a less differentiated pattern (arrows) than those of mucosal and submucosal lesions. f Magnified view showed a cyst-like lesion lined by a single layer of presumed benign cells (arrow).
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case_images: PMC10718579_01_cro-2023-0016-0001-533363_F03.jpg
case_images: F3
case_images: Well-differentiated atypical cells distributed from the mucosa to the serosa at the elevated lesions and spread widely, i.e., 150 x 135 mm, in the gastric submucosa (Fig. 3a). Large cyst-like lesions, lined with a single layer of presumed benign cells, were observed in the gastric submucosa (Fig. 3b-d). Judged by these pathological findings, we highly speculated that well-differentiated invasive adenocarcinoma cells originating from the submucosal ectopic gastric gland spread widely in the submucosa and partially protruded into the gastric lumen through the disruption of the gastric mucosa in this case (Fig. 3e).