[A Case of Resected Gastric Cancer Occurring Simultaneously with Intrahepatic Cholangiocarcinoma after S-1 plus Cisplatin Chemotherapy].

It is sometimes difficult to differentiate between metastatic and primary liver tumors, when the liver tumor occurs simultaneously with a gastric cancer. We encountered a case of resected gastric cancer, which occurred concomitantly with intrahepatic cholangiocarcinoma after S-1 plus cisplatin chemotherapy, in a patient who was previously diagnosed with metastatic liver tumor before treatment. An 80-year-old man was admitted to our hospital because of epigastralgia. Endoscopic study of the upper gastrointestinal tract showed a type 3 tumor at the upper body of the stomach. A plain CT scan showed an irregular, low-density area, which was enhanced by contrast medium in the lateral segment of the liver. We performed an ultrasound- guided needle biopsy, because it was impossible to make a definitive diagnosis by dynamic CT, contrast-enhanced ultrasonography, and MRI. Immunohistochemical analysis for cytokeratin 7/20 resulted in 7 (+)/20 (-) for both the gastric cancer and the liver tumor. Therefore, we diagnosed the patient with gastric cancer, which occurred concomitantly with the metastatic liver tumor, and administered chemotherapy with S-1 plus cisplatin. After 3 courses of the regimen, a reduction in the size of mass was observed in the stomach and the liver. We subsequently performed left hepatectomy and total gastrectomy with lymph node dissection. Microscopic examination revealed the gastric cancer, which occurred simultaneously with the intrahepatic cholangiocarcinoma. The postoperative course was uneventful, and the patient remains well without recurrences.