[A Case of Undifferentiated Sarcoma of the Liver in an Adult Treated with Right Hepatectomy Followed by Adjuvant Chemotherapy].

Undifferentiated sarcoma of the liver is rare, especially in adults, and is an aggressive malignancy that originates from the primary mesenchymal tissues. A 53-year-old man was referred to our hospital for further evaluation of a low-grade fever. Contrast-enhanced CT revealed an 18-cm tumor in the right lobe of the liver. The tumor was characterized by low-density areas suspected of cystic components, a high-density area suspected of hemorrhage, and contrast enhancement in the thickened marginal and internal septa. MRI revealed a high-intensity tumor with a heterogeneous structure on T2-weighted images. Angiosarcoma of the liver with intratumoral hemorrhage was suspected, and right hepatectomy was performed. The pathological diagnosis was an undifferentiated sarcoma based on the presence of undifferentiated mesenchymal tumor cells with a stellate to spindle-shaped pleomorphism. Following a multidisciplinary discussion, 4 courses of the AI regimen (doxorubicin and ifosfamide)were administered as adjuvant chemotherapy, and no recurrence was confirmed at 2 years and 6 months follow-up. Our case suggests that radical resection followed by adjuvant chemotherapy may contribute to a favorable prognosis for undifferentiated sarcoma of the liver.