Undifferentiated embryonal sarcoma of liver

Abstract Undifferentiated embryonal sarcoma of the liver (UESL) is a rare, malignant, mesenchymal tumor that is commonly observed in children. The symptoms and imaging characteristics of UESL are not specific and can be mimicked by other tumors or liver abscesses. The tumor often appears as a large, heterogeneous, echoic solid mass with small cystic areas, presenting a cyst-like appearance on computed tomography (CT) and magnetic resonance imaging (MRI). The histopathological manifestations of UESL consist of stellate-shaped and spindle cells scattered on a myxoid background, with high mitotic counts. Cells with multiple or bizarre nuclei can also be observed. Here, we illustrate a 9-year-old male diagnosed with UESL by describing the imaging and histopathological characteristics that resulted in the diagnosis.