case_images: PMC11079201_01
case_images: Endoscopic images. Endoscopic examination revealed a 30-mm, flat, elevated lesion on the lesser curvature of the middle gastric body (arrow) (A). NBI showed a defined, slightly faded elevated area within a demarcation line (arrows) (B). M-NBI revealed that the lesion exhibited the vessels within an epithelial circle pattern. A dilated and irregular microvascular pattern was observed in the circular intervening part between crypts lined by circular marginal crypt epithelium (C). The circular marginal crypt epithelium was traced (D).
case_images: fonc-14-1396281-g001.jpg
case_images: PMC11079201_01_fonc-14-1396281-g001.jpg
case_images: f1
case_images: The background of the lesion mucosa was pale, the mucosal vessels' visibility increased, and the gastric folds disappeared, which were the specific features of atrophic gastric mucosa ( Figure 1A ). The narrow-band imaging (NBI) result showed a well-defined, slightly faded elevated area within a demarcation line ( Figure 1B ), and the size of the lesion was approximately 30 mm. The microvascular architecture showed dilated and tortuous atypical vessels with differences in the caliber ( Figures 1C, D ).
case_images: Pathohistological images of the resected specimen. Low-power field (A) and high-power field (B-D) images of hematoxylin and eosin-stained specimens. The scale bars represent 800 mum (A), 200 mum (B), 40 mum (C, D), and 100 mum (E). The blue arrows show the boundaries of the tumor (A). The blue frame indicates the lesion's superficial dense tubular and papillary structures and deeper pyloric gland-like glandular ducts (B). The tumor cells were similar to foveolar epithelium (C) and pyloric gland cells (D) with low-grade cell atypia and obvious architectural atypia. A lymphovascular invasion was visible (indicated by the black arrow) (E).
case_images: fonc-14-1396281-g002.jpg
case_images: PMC11079201_01_fonc-14-1396281-g002.jpg
case_images: f2
case_images: The histopathologic examination of the resected specimen revealed that the surrounding mucosa of the elevated lesion was atrophic gastric fundic glands with intestinal metaplasia ( Figure 2A ). The lesion was located in the mucosal layer with a LVI ( Figure 2E ). Moreover, the deeper layer of the lesion was pyloric gland-like glandular duct ( Figure 2B ). The nuclei of the lesion were round to oval with disturbed polarity, and the cell cytoplasm was translucent and rich in mucus but lack mucus stratification ( Figure 2C ). Figure 3A ). Furthermore, the deep pyloric gland-like cells, which were positively stained for MUC6 ( Figure 3B ), proliferated and differentiated to form irregular, fused glandular ducts and eventually led to the pyloric gland-type tubular adenocarcinoma ( Figure 2D ).
case_images: Phenotypic marker expression by immunohistochemistry staining with MUC5AC (A), MUC6 (B), MUC2 (C), CD10 (D), Ki-67 (E), P53 (F), MSH2 (G), and MSH6 (H). The scale bars represent 160 mum. The superficial foveolar-type papillary adenocarcinoma was positive for MUC5AC. The deep pyloric gland-type tubular adenocarcinoma was positive for MUC6. Both layers (the superficial part and the deep part) were negative for MUC2 and CD10. The expression of Ki-67 was high in the superficial foveolar-type papillary adenocarcinoma but low in the deep pyloric gland-type tubular adenocarcinoma. P53 was wild-type expression. The expression of MSH2 and MSH6 protein was lost.
case_images: fonc-14-1396281-g003.jpg
case_images: PMC11079201_01_fonc-14-1396281-g003.jpg
case_images: f3
case_images: Figure 3A ). Furthermore, the deep pyloric gland-like cells, which were positively stained for MUC6 ( Figure 3B ), proliferated and differentiated to form irregular, fused glandular ducts and eventually led to the pyloric gland-type tubular adenocarcinoma ( Figure 2D ). Both layers, namely, the superficial part and the deep part, displayed negativity for MUC2 ( Figure 3C ) and CD10 ( Figure 3D ), which was consistent with gastric type adenocarcinoma. The Ki-67 labeling index was high in the superficial foveolar-type papillary adenocarcinoma but low in the deep pyloric gland-type tubular adenocarcinoma ( Figure 3E ), and P53 was a wild-type expression ( Figure 3F ) in the lesion. The expression of MSH2 ( Figure 3G ) and MSH6 ( Figure 3H ) protein was lost.
case_images: Pathological recovery diagrams. Very well-differentiated gastric adenocarcinoma of gastric type, pT1a (M), Ly1, V0, pHM0, and pVM0. The specimen was 44 mm x 32 mm and type 0-IIa, and the cancerous lesion was 18 mm x 16 mm with a red marking in the yellow circle.
case_images: fonc-14-1396281-g004.jpg
case_images: PMC11079201_01_fonc-14-1396281-g004.jpg
case_images: f4
case_images: Therefore, the final pathological diagnosis was a type 0-IIa, 18 mm x 16 mm, VWDA of gastric type, pT1a, Ly1, V0, pHM0, and pVM0 ( Figure 4 ).