case_images: PMC10601832_01
case_images: Preoperative tests. a Gastroendoscopy shows a central ulcerated area surrounded by rough, protruding border. b Hematoxylin-eosin (H&E) stain (original magnification, x10) of endoscopic biopsy specimen illustrates malignant cells arranged in irregular glandular structures. c, d Abdominal CT scan shows lesser curvature lesion of the stomach (red arrow) and enlarged regional lymph node (blue arrow).
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case_images: F1
case_images: Gastroendoscopy found a lesion which an irregular protruding border combined with a central ulcerated lesion 2.5 cm in size located in the minor curvature of the stomach (Fig. 1a). The pathology of the biopsy tissue was invasive adenocarcinoma (Fig. 1b). Abdominal CT scan illustrated a gastric wall lesion, sized 12 x 30 mm, with loss of layer structure without serosa invasion (Fig. 1c) combined with a few lymph nodes suspected of metastasis, with the biggest measuring 11 x 18 mm (Fig. 1d).
case_images: H&E stains of resected specimen. a Two components without clear boundary (original magnification, x4). b Moderately differentiated adenocarcinoma component (original magnification, x40). c NET component (original magnification, x40).
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case_images: PMC10601832_01_cro-2023-0016-0001-533707_F02.jpg
case_images: F2
case_images: Microscopy of the resected tissue visualized epithelial cells with deformed nuclei and alkaline rough chromatin organized in glandular shapes (Fig. 2b). This component coexisted with solid nests comprising relatively uniform aberrant cells with fine chromatin and conscious nucleoli (Fig. 2c), displaying eight mitoses per 10 high-power fields.
case_images: Immunohistochemistry stainings for resected specimen. Neuroendocrine constituent: positive with AE 1/3 (a), positive with synaptophysin (b), positive with chromogranin A (c), Ki 67 16.5% (d). Muscle invasive adenocarcinoma part: positive with AE 1/3 (e), negative with SP 11 (f), negative with chromogranin A (g), Ki 67 51% (h).
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case_images: PMC10601832_01_cro-2023-0016-0001-533707_F03.jpg
case_images: F3
case_images: Both constituents had AE 1/3 stains (Fig. 3a, e). Chromogranin A and synaptophysin were positive in the solid nest portion (35%) but negative in the adenocarcinoma (65%) (Fig. 3b, f, c, g). Ki 67 was 16.5% and 51% in the neuroendocrine sections and the adenocarcinoma structure, respectively (Fig. 3d, h). The local invasive structure and metastasis regional lymph nodes were stained with AE 1/3 but not with chromogranin A or synaptophysin (Fig. 3e, f, g, and Fig. 5).
case_images: Immunohistochemistry stainings for MMR protein expression of resected tissue. Adenocarcinoma part: deficient expression of MLH1 (a), deficient expression of PMS2 (b), intact expression of MSH2 (c), intact expression of MSH6 (d). Neuroendocrine component: deficient expression of MLH1 (e), deficient expression of PMS2 (f), intact expression of MSH2 (g), intact expression of MSH6 (h). b, f Both imaging reveal background staining in the acceptable positive internal control.
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case_images: F4
case_images: Loss of display proteins MLH1 and PMS2 and proficient staining proteins MSH2 and MSH6 were both parts of the neoplasia (Fig. 4).