[A Case of Surgical Resection of a Liver Metastasis from Colorectal Cancer with a Macroscopic Portal Vein Tumor Thrombus].

The patient was a 65-year-old man. In July 2014, he was diagnosed with rectal cancer in a different hospital and underwent high anterior resection(type 2, T3N0M0, StageⅡ [TMN classification, 7th edition]). During the operation, a small nodule was detected in segment 4 of the liver. Contrast-enhanced abdominal CT revealed a tumor measuring 5 cm in diameter located in segment 4/8 of the liver with a tumor thrombus in the main trunk of the portal vein. In August 2014, the patient was referred to our hospital for further examination and treatment. MR imaging showed a lobulated tumor located in segment 4/8 of the liver. Gadoxeticac id-enhanced hepatobiliary phase MR imaging showed that the tumor was less enhanced than was the adjacent liver parenchyma. 18F-FDG-PET/CT demonstrated abnormal accumulation of 18F-FDG in the main tumor(SUVmax=18.3). There was no obvious abnormal accumulation in the other organs. In September 2014, he underwent extended left hepatectomy and portal vein tumor thrombectomy. The resected specimen showed a well-differentiated adenocarcinoma. Immunohistochemical staining results were CK7/CK20 (-/+) and CDX2 (+), which suggested that the tumor was derived from the gastrointestinal tract rather than the liver. The pathological diagnosis was a liver metastasis from rectal cancer. In the 6 months after the operation, intrahepatic recurrence was detected, and the patient was treated with systemicchemotherapy.