[Retroperitoneal metastasis of hepatocellular carcinoma - a case report].

The patient was a 54-year-old man. He was an HBV carrier, and hepatocellular carcinoma (HCC) was detected for the first time in 2000. An operation was performed, but HCC recurred. After repeating the operation and transarterial chemo-embolization (TACE) for the recurrent HCC, a tumor was found in January 2009 on the ventral side of the right kidney, and we thought it was a retroperitoneal metastasis of HCC or peritoneal dissemination. He was enrolled in a trial of systemic chemotherapy, called "S-1 monotherapy for extrahepatic metastasis of HCC", but the tumor seemed progressive. Since he showed no other lesion, he was indicated for surgical resection. Intraoperatively, the tumor was localized between the duodenum and the right kidney, and was covered by the retroperitoneum. Pathological examination of the resected specimen revealed retroperitoneal metastasis of HCC. Intrahepatic recurrence was detected 6 months after the resection. Therefore, he underwent TACE, and he is currently (1 year after surgery) alive without any extrahepatic metastasis. We describe herein this case because retroperitoneal metastasis of HCC is very rare.