Embryonal sarcoma of the liver in an adult patient.

Undifferentiated embryonal sarcomas (UESs) are uncommon tumours that are seen predominantly in late childhood. Cases in adults are rare and generally present once a large mass develops and may be mistaken for other tumours. A case of an UES of the liver with an isolated peritoneal metastasis is described. The patient presented with a palpable mass with imaging findings suggestive of a cystic tumour. She had complete surgical resection of the liver mass and isolated peritoneal metastasis. She was tumour-free on imaging at 6 months without adjuvant chemotherapy. An UES should be considered in the differential of large cystic hepatic lesions, with aggressive surgical resection considered when possible.