Undifferentiated sarcoma of the liver in an adult showing early recurrence after hepatectomy and rapid growth leading to death

A 42-year-old woman was admitted to our hospital because of right hypochondrial pain. Enhanced CT identified a tumor protruding caudally from segment 5/6 of the liver, and the lesion was 8×6 cm in size. The tumor was composed of a slightly enhanced solid lesion and an unenhanced septate cystic lesion. MRI also revealed a tumor composed of solid and liquid components. PET-CT revealed no other malignant lesion other than the liver tumor. From these results, we preoperatively diagnosed the tumor as sarcoma of the liver, and partial liver resection including the tumor was performed. Tumor invasion to the colon was suspected, and the invaded colon was also excised. The tumor was diagnosed as undifferentiated sarcoma of the liver with partial rhabdoid differentiation based on histopathological findings. Multiple recurrent tumors were recognized in the remnant liver and peritoneum on CT 42 days after surgery. Chemotherapy consisting of doxorubicin and pazopanib was not effective, and the patient died 89 days after surgery. Undifferentiated sarcoma of the liver is a mesenchymal malignant tumor occurring in the liver. The tumor appears more commonly in childhood, and it is rare in adults. Multimodality therapy including chemotherapy should be used to improve prognosis.