Pre-operatively misdiagnosed undifferentiated embryonal sarcoma of the liver: analysis of 16 cases

Undifferentiated embryonal sarcoma of the liver (UESL), also known as malignant mesenchymal tumor, embryonal sarcoma (1), or fibromyxoid sarcoma, is an extremely rare malignancy that arises from liver mesenchymal tissue. It is highly malignant and invasive, ranking the fourth among childhood liver tumors (after hepatoblastoma, infantile hemangioendothelioma, and liver cancer) (2). It accounts for about 13% of pediatric primary liver cancers (3), particularly in populations aged 6-10 years (90% of the patients are younger than 15 years) (4). Since UESL is mainly seen in young children and adolescents (5) and is rare among adults, its clinical symptoms in the early stage may not by typical, and its laboratory and radiological findings are also non-specific. The prevalence of hepatitis is high in China. In the adult UESL patients, the disease is often accompanied by hepatitis, cirrhosis, or liver dysfunction, making the pre-operative diagnosis of UESL extremely difficult. As a result, UESL is often misdiagnosed as other tumors, and the patients often have a short survival after the disease is finally confirmed (6). In our current study, we analyzed the clinical and imaging data of 16 UESL patients whose disease was misdiagnosed during the period from 2009 to 2014, with an attempt to improve the pre-operative diagnosis accuracy