A 57-year-old male patient presented to the local hospital in July 2017 for "epigastric pain and discomfort for one month". Gastroscopy showed a large ulcer in the gastric antrum, and biopsy pathology showed poorly differentiated carcinoma, tending to poorly differentiated adenocarcinoma. The patient was admitted to our hospital for surgical treatment. Physical examination showed that there was only mild tenderness in the upper abdomen without rebound pain, no palpable abdominal mass, no obvious jaundice in the skin and sclera, and no obvious enlargement of superficial lymph nodes. Serological examination showed that total bilirubin (TBILI) decreased (1.8umol/L, normal range 7.4-24.1umol/L), hemoglobin (HGB) decreased (93g/L, normal range 120-160g/L), carbohydrate antigen (CA) 724 increased slightly (7.66U/ml, normal range 0-6.9U/ml), carcinoembryonic antigen (CEA), CA19-9, CA125, alpha-fetoprotein (AFP) were all in the normal range. Thorax and abdomen plain scan and contrast-enhanced CT ( Figures 1A   -F ) showed gastric cancer thickening in the gastric antrum, considering the tumor, and the tumor was not clearly demarcated from the left lobe of the liver; the size and shape of the liver were normal, the edge was smooth, and no abnormal density and enhancement lesions were found in the parenchyma. Small lymph nodes could be seen in the hepatogastric space, but no obvious enlarged lymph nodes were found in the retroperitoneum. We initially diagnosed it as gastric antrum malignant tumor. After multidisciplinary tumor consultation, we decided to carry out surgical treatment.
After excluding surgical taboos, the patient underwent surgery in August 2017. During the operation, the tumor was located in the gastric antrum, about 5 x 4cm in size, infiltrated into the serosa, the anterior wall adhered closely to the left lateral lobe of the liver, and the posterior wall adhered closely to the transverse colon. Enlarged lymph nodes could be seen around the tumor, but there were no obvious metastatic nodules in the liver, peritoneum, and transverse colon. The family members and trustees of the patients were informed of the intraoperative findings, the details of possible adverse prognoses, and the advantages and disadvantages of different surgical methods. After obtaining their consent and signing the informed consent form, we performed radical distal gastrectomy (Billroth II gastrointestinal reconstruction) and partial left lateral lobectomy of the liver ( Figure 1G ). The operation time was about 200min, the blood loss was about 200ml, no blood transfusion was performed. The postoperative pathology showed that the tumor was poorly differentiated adenocarcinoma. The tumor was closely related to the liver tissue, invading the entire layer of the gastric wall to the mucosa from outside to inside and accompanied by ulcer formation. Tumor cells could be seen in the lymphatic vessel, and the nerve was not invaded. 27 lymph nodes were dissected. None of these lymph nodes metastasized. Immunohistochemical staining showed that the tumor tissue expressed broad-spectrum cytokeratin (CKpan), CK-7, and CK-19, but not CK-20, S-100, CD-10, Heppar-1, CD-56, synaptophysin (Syn), chromogranin A (CgA), and Ki67 proliferative index was approximately 70% ( Figures 2 ). After communicating with pathologists and considering the immunohistochemical results, we considered gastric metastasis from intrahepatic biliary adenocarcinoma.
The patient recovered smoothly without obvious postoperative complications and was discharged 11 days after the operation. We performed 8 cycles of chemotherapy with the gemcitabine + capecitabine regimen. The first chemotherapy begins one month after the operation, followed by the next cycle of chemotherapy at an interval of 21 days. The patients were reexamined every 3 months after the operation for 2 years and every 6 months after the operation for 3-5 years. No tumor recurrence or metastasis was found 5 years after the operation, and the patient is still alive.