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case_images: A, B, C, D. Endoscopic examination showed a submucosal appearing lesion in the posterior wall of the proximal gastric body (1A). The lesion had an irregular microsurface pattern and microvascular pattern in the magnifying blue laser imaging (1B). Biopsy revealed atypical glands without architectural atypia and nuclear atypia (H&E, x100 (1C), x200 (1D)).
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case_images: The first endoscopic examination revealed a lesion with depressions in the center on the surface, but protruding as a whole and appeared like a submucosal tumor, located on the posterior wall of the proximal gastric body (Fig. 1A). It had an irregular microsurface pattern and microvascular pattern using magnifying blue laser imaging (Fig. 1B). The glands were comprised of eosinophilic columnar epithelium and a few scattered goblets cells with low-grade nuclear atypia (Fig. 1C, D).
case_images: Endoscopic ultrasonography showed a low echoic tumor extending into the fourth layer of the gastric wall.
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case_images: EWDA was considered, reactive intestinal metaplasia was not excluded. Endoscopic ultrasonography showed a low echoic tumor growing into the fourth layer of the gastric wall (Fig. 2).
case_images: A, B, C. Endoscopic submucosal dissection was of the lesion was performed (3A). The histopathologic examination of the specimen showed acidophilic columnar cancer cells indicating mild to moderate nuclear atypia infiltrated deeper than the submucosal layer with forming mucinous glands clearly. Both horizontal and vertical margins were positive (H&E, x40 (3B), x100 (3C)).
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case_images: Therefore, as a partial dissection to obtain an adequate sample of tissue from deeper in the lesion, an endoscopic submucosal dissection to establish a definitive diagnosis was performed (Fig. 3A). The tumor had obvious involvement of both the lateral and vertical margins indicating incomplete dissection (Fig.3B, C).
case_images: A, B, C. Laparoscopic total gastrectomy was performed. The resected tumor had acidophilic columnar cancer cells indicating mild to moderate nuclear atypia infiltrating the mucosal layer to the subserosa with clear formation of mucinous glands (H&E, x12.5 (4A), x200 (4B), x100 (4C)).
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case_images: Pathological examination of the resected stomach revealed that the tumor infiltrated the subserosa with moderate vascular invasion (Fig. 4A-C).