[A Case of Hepatocellular Carcinoma Complicated by Liver Metastasis of Colon Cancer during the Course of Treatment].

A 72‒year‒old man with hepatocellular carcinoma(HCC)was treated with transarterial chemoembolization(TACE)and radiofrequency ablation(RFA). Six months after RFA, gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid(Gd‒ EOB‒DTPA)‒enhanced magnetic resonance imaging(MRI)revealed multiple metastatic recurrences in the liver. TACE was performed for the recurrent HCC. However, the treatment response on the Gd‒EOB‒DTPA‒enhanced MRI showed that the lesions had advanced and that the liver metastatic nodules had ring‒shaped contrast effects. We suspected metastatic liver cancer based on the MRI findings and performed colonoscopy. Finally, we diagnosed the patient with multiple hepatic metastases of sigmoid colon cancer based on the results of the endoscopic colon biopsy and percutaneous liver tumor biopsy. In conclusion, we had a teachable case of the treatment of HCC.

Microsatellite Instability-high Intrahepatic Cholangiocarcinoma with Portal Vein Tumor Thrombosis Successfully Treated with Pembrolizumab.

A 60-year-old man presented with postoperative recurrence of intrahepatic cholangiocarcinoma with right portal vein tumor thrombosis (PVTT). After failure of standard chemotherapy, a liver biopsy showed that his microsatellite instability (MSI) status was high. Treatment with the immune checkpoint inhibitor (ICI) pembrolizumab was commenced, which resulted in a partial response and resolution of the PVTT. There were no significant immune-related adverse events. According to recently published reports, the frequency of MSI-high biliary tract cancer (BTC) is about 0-2.1%, which is extremely rare. However, ICIs may be effective in patients with MSI-high BTC, such as the present patient.