Undifferentiated embryonic sarcoma of the adult liver with paraneoplastic syndrome: a case report.

Background: Undifferentiated embryonic sarcoma of the liver (UESL) is a rare primary liver sarcoma that mainly affects children. Since it was first reported in 1978, less than 100 cases of UESL in adults have been reported. Due to the lack of specificity of clinical symptoms and imaging findings, the misdiagnosis rate of UESL is very high, and the definite diagnosis is usually in the late stage. Paraneoplastic syndrome (PNS) is a clinical symptom caused by the production of hormones or hormone-like substances in some tumors. This report describes the clinical diagnosis and treatment of patients with these 2 rare disorders. The imaging, histological, and genetic manifestations of UESL are described. This study provides support for the clinical research progress of UESL. Case Description: We report the case of a 57-year-old male with UESL and a progressive abdominal mass. Preoperative fine needle aspiration cytology (FNAC) of intrahepatic mass and postoperative routine pathology showed UESL. Ultrasound examination showed solid intrahepatic mass. Both computed tomography (CT) and magnetic resonance imaging (MRI) showed a large necrotic lesion in the right lobe of the liver. Laboratory examination showed leukocytosis [white blood cells (WBC): 10,005/µL]. The percentage of neutrophils increased (Ne%: 85%). Blood glucose was increased [glucose (Glu): 19.27 mmol/L]. Moderate anemia was observed [hemoglobin (Hb): 64 g/L]. Serum tumor markers (including AFP, PIVIKA, CA19-9, and CEA) were normal. Hepatitis virus markers [hepatitis B surface antigen (HBsAg) and antibodies to hepatitis C virus (anti‑HCV)] were negative. The patient presented with paraneoplastic symptoms such as fever, cough, night sweats, hyperinflammation, and hyperglycemia before surgery. After right hemihepatectomy, the paraneoplastic symptoms disappeared completely, and there was no recurrence in the follow-up for six months. Conclusions: UESL is rare, especially in adults. The clinical manifestations of UESL are very similar to those of liver abscess and liver cystic tumor at the initial stage of the disease, for which differentiation is necessary. UESL should be considered when there is large cystic liver disease. FNAC is a good way to confirm the diagnosis. Complete resection of the tumor and postoperative chemotherapy is still the main treatment for UESL. The long-term effects of the therapeutic agents identified by genetic testing in this patient on the disease remain to be seen.