fa قلب Heart گزارش مورد case report <div><strong>Background:</strong> Hepatic tumors are rare in children comprising only 1% - 4 % of all childhood solid tumors. Primary sarcomas of the liver are extremely rare and represent approximately 0.2 % of all liver tumors. Undifferentiated embryonal sarcoma of liver is an aggressive tumor with an unfavorable prognosis. Here we reported a case of undifferentiated embryonal sarcoma of liver in a 9-year-old boy who was misdiagnosed as&nbsp; hydatid cyst of liver.<br> <strong>Case Report: </strong>An 8-year-old male patient was referred to our hospital following unsuccessful surgery for presumed hydatid disease of the right lobe of liver. Computed tomography (CT) and ultrasonography showed a large hepatic mass. Following the surgery, our patient received adjuvant chemotherapy. At the time of writing, it has been one year after the termination of adjuvant chemotherapy. Follow up imaging studies, including ultrasonography, CT scan, and MRI show no evidence of recurrence.<br> <strong>Conclusion</strong>: Here we reported a case of undifferentiated embryonal sarcoma of liver in a 9-year-old boy mistaken for hydatid cyst of liver. Based on our observation, undifferentiated embryonal sarcoma of liver should be considered as a differential diagnosis among patients suspected of hydatid cyst of liver.<br> &nbsp;</div> Childhood Liver Tumors, Hydatid Cyst, Undifferentiated Embryonal Sarcoma of Liver 247 251 http://ijpho.ssu.ac.ir/browse.php?a_code=A-10-542-2&slc_lang=fa&sid=1 Mozhgan Hashemieh Yes Research and Development Center, Imam Hossein Medical Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran Research and Development Center, Imam Hossein Medical Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran