Background: Undifferentiated embryonal sarcoma (UES) of the liver is a rare, highly malignant neoplasm with a poor prognosis occurring almost exclusively in late childhood (6-10 years of age). Only a few cases have been reported in adults, accounting for less than 1% of all primary liver neoplasms.
Methods: A 47-year-old woman presented with a palpable mass in the left upper abdomen. Magnetic resonance imaging revealed a 12x10 cm cystic mass with hemorrhage in the left lateral segment of the liver. The initial impression was a hemorrhagic cystic tumor of the liver. The patient underwent a left lateral sectionectomy of the liver. Histopathology and immunohistochemistry helped make a diagnosis of UES.
Results: The patient recovered uneventfully and received systemic chemotherapy. Radiologic examination for follow-up revealed a metastatic lesion in the lumbar spine (L5). She was subjected to radiotherapy at the lumbar spine. She survived 48 months.
Conclusion: Although hepatic cyst as UES of the liver is difficult to diagnose because of its rarity in adults and lack of specific findings, it should be considered in a differential diagnosis.