Undifferentiated embryonal sarcoma of the liver in an 11-year-old boy: a case report and clinical insights.

This case report presents the clinical course and management of an 11-year-old boy who was diagnosed with undifferentiated embryonal sarcoma of the liver (UESL), a rare and aggressive pediatric malignancy. The patient was admitted with a 20-day history of right upper quadrant pain. Imaging studies revealed a large cystic-solid mass in the right hepatic lobe, suggestive of UESL, with involvement of major hepatic vessels and the diaphragm. The patient underwent a successful extended right hepatectomy (right trisectionectomy) via an anterior approach. The postoperative course was complicated by bile leakage, which resolved with conservative management. Adjuvant chemotherapy was subsequently administered. The patient recovered fully and was disease-free at follow-up. This case highlights the critical importance of a multidisciplinary approach, meticulous surgical planning, and the utility of the anterior approach for resecting large liver tumors. It also underscores the necessity of considering UESL in the differential diagnosis of pediatric liver masses and the role of multimodal therapy in achieving a favorable outcome. Clinical lessons from this case are discussed in the context of current management strategies, with emphasis on complete resection and organized post-discharge surveillance.