PMC10353555_01
Endoscopic finding before treatment. On esophagogastroduodenoscopy before treatment, an irregular ulcerative tumor in the middle to lower stomach and the pyloric ring was constricted so that the scope could barely pass through it.
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EGD could barely pass through it (Figure 1). Endoscopically, the lesion was diagnosed as a type 3 advanced gastric cancer.
Histopathological findings of biopsied primary gastric cancer. (a) On hematoxylin and eosin staining, alveolar and solid proliferation of tumor cells with hyperchromatic and enlarged nuclei with occasional glandular lumina were detected. (b) On immunostaining, the tumor cells were negative for HER2.
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Pathological examination of the endoscopic biopsy specimen from this region indicated poorly differentiated adenocarcinoma, and immunostaining for human epidermal growth factor type 2 (HER2) was negative (Figure 2a and b).
Radiological findings before treatment. (a and b) On contrast-enhanced computed tomography before treatment, a thickening of the wall of the middle to lower stomach (black arrows) and a swollen left supraclavicular lymph node (white arrows) were detected.
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Contrast-enhanced computed tomography (CT) revealed thickening of the wall of the middle to lower stomach and a swollen left supraclavicular LN (Figure 3a and b).
Endoscopic and radiological findings after pre-operative treatment. (a) On esophagogastroduodenoscopy after 3 courses of pre-operative treatment, an irregular ulcerative tumor had shrunk, mucosal irregularities had disappeared, and scarring was observed. (b and c) On contrast-enhanced computed tomography after 3 courses of pre-operative treatment, a thickening of the gastric wall (black arrows) and the size of swollen left supraclavicular lymph node (white arrows) were decreased. (d and e) On PET-CT after 3 courses of pre-operative treatment, a mild accumulation was still present in the stomach (SUVmax 3.33: black arrows) and there was no abnormal accumulation in a left supraclavicular lymph node (white arrows). (f) On plain chest computed tomography after 3 courses of pre-operative treatment, a mild ground glass opacity was detected.
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After three courses of treatment, EGD revealed that the primary gastric cancer had shrunk, and no mucosal irregularities were observed (Figure 4a). Contrast-enhanced CT detected decreased gastric wall thickening and reduced size of the swollen Virchow's LN (Figure 4b and c). PET-CT showed that mild accumulation was still present in the stomach (SUVmax 3.33); however, there was no abnormal accumulation in Virchow's LN (Figure 4d and e). As an adverse effect, chest CT revealed grade 1 interstitial pneumonia (Figure 4f), and the serum level of KL-6 increased to 1162 U/mL, but no clinical respiratory symptoms were present. 
Histopathological findings of Virchow's lymph nodes and primary gastric cancer by the resected specimen. (a) On hematoxylin and eosin staining of the resected Virchow's lymph nodes, there is coagulation necrosis (*) surrounded with histiocyte. There are no viable cancer cells. (b) On immunohistochemical staining for cytokeratin (clone AE1/AE3) of the resected Virchow's lymph nodes, the necrotic regions were stained, indicate of necrotic change of cancer cells. (c, d) On hematoxylin and eosin staining of the resected stomach, mucosa (c) and muscularis propria (d) failed to show any viable cancer cell.
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No viable cancer cells were found inside the resected LN (Figure 5a and b).  Histopathological examination revealed complete degeneration of the primary tumor and regional LN without any residual carcinoma (Figure 5c and d), and the histological response of the tumor was categorized as grade 3.