Sarcomatoid Intrahepatic Cholangiocarcinoma After Immunotherapy: A Case Report and Review of the Literature.

Sarcomatoid carcinoma is a rare tumor that is composed of a mixture of malignant epithelial cells and mesenchymal cells. Many studies have reported that sarcomatoid carcinoma occurs in multiple organs including the liver. Sarcomatoid intrahepatic cholangiocarcinoma (S-iCCA) is an extremely rare tumor that primarily occurs in the liver. This case occurred in a middle-aged man who was admitted to our hospital with abdominal pain. Enhanced computed tomography of the abdomen showed a low-density mass in the upper right posterior lobe of the liver with enhancement in the periphery. Histological and immunohistochemical examination indicated that the tumor was malignant, with both cancer and sarcoma components, and was positive for cytokeratin and vimentin. The patient was diagnosed with S-iCCA. Metastases appeared in the liver and lung 4 months after surgery. Two cycles of chemotherapy were administered. Because of enlargement of the tumor, anti-angiogenic agents combined with immunotherapy were subsequently given to achieve disease control. To the best of our knowledge, this is the first reported case of a programmed cell death-1 inhibitor used in a S-iCCA patient. The purpose of this case report and literature review is to enhance clinician understanding of S-iCCA and to explore safe and effective treatment methods.