Undifferentiated Embryonal Sarcoma of the Liver: First Case Reported in Central America.

Background: Undifferentiated embryonal sarcoma of the liver (UESL) is a rare and aggressive mesenchymal tumor, typically occurring in children. It poses significant diagnostic challenges due to its atypical presentation and rarity in clinical practice.

Case: We report the first case in Central America of a 19-year-old female presenting with chronic abdominal pain and a liver mass. Imaging revealed a solid and cystic lesion in the liver, and a subsequent complete surgical resection confirmed the diagnosis of UESL. The patient received adjuvant chemotherapy and has been disease-free for 34 months.

Conclusion: This case highlights the importance of complete surgical resection combined with chemotherapy to improve prognosis in UESL. Our findings emphasize the need to consider UESL in differential diagnoses of liver lesions, especially in regions where it has not been previously reported.