A case of undifferentiated embryonic liver sarcoma mimicking cystic hydatid disease in an endemic region of the world.

Undifferentiated embryonic liver sarcoma (UELS) is a rare highly malignant neoplasm that predominantly occurs in children between 5 and 10 years of age. The typical radiologic appearance on ultrasound and computed tomography of UELS shows a large septated mass having combined cystic and solid components. These radiographic features, however, are not specific to UELS and are shared by other more common and benign diseases of the liver. For example, cystic hydatid disease (CHD), caused by larvae of the Echinococcus tapeworm, is the most common indication for hepatic operations in children residing in endemic regions of the world. Undifferentiated embryonic liver sarcoma and CHD are 2 diseases that share overlapping presenting features of patient age, symptoms, and radiologic appearance. Surgeons who operate in Echinococcal endemic regions must be aware that not all hepatic cystic masses are necessarily CHD and may be other more rare malignant diseases such as UELS.