{Reference Type}: Case Reports {Title}: An Adult With Undifferentiated Embryonal Sarcoma of the Liver: A Case Report of a Rare Encounter. {Author}: Rammohan R;Joy M;Magam SG;Patel A;Magam SR;Natt D;Desai J;Bunting S;Mustacchia P; {Journal}: Cureus {Volume}: 15 {Issue}: 9 {Year}: 2023 Sep 暂无{DOI}: 10.7759/cureus.45018 {Abstract}: Undifferentiated embryonal sarcoma of the liver (UESL) is a rare, aggressive tumor mainly found in children but can also appear in adults. Its diagnosis in adults remains a conundrum; it is often identified late due to its non-specific symptoms and resemblance to benign lesions. A comprehensive treatment regimen involving surgical intervention, chemotherapy, and possibly radiation significantly boosts survival rates. Imaging often yields inconclusive outcomes, further complicating the diagnostic process. Here, we report the case of a 28-year-old female diagnosed with UESL, emphasizing the need for timely intervention. Undifferentiated embryonal sarcoma of the liver requires differentiation from a variety of hepatic tumors in adults. Though there are no distinctive characteristics to differentiate UESL from other hepatic masses, its morphology and immunohistochemical profiles significantly vary. The staging often reveals UESL as a large, well-defined mass with the potential for diverse differentiation. Its prognosis has been considerably improved with the advent of multidisciplinary treatment. Surgical resection remains a cornerstone, often combined with chemotherapy. While pediatric cases exhibit better overall survival rates than adults, outcomes heavily depend on the chosen treatment regimen. A combination of chemotherapy and complete tumor removal has been found to significantly elevate survival chances. Disease recurrence remains a challenge and is influenced by treatment strategy. In conclusion, the diagnosis and treatment of UESL are fraught with challenges, particularly in adults. A multidimensional approach, combining various therapies, is paramount for better outcomes. Continuous research and enhanced awareness are crucial for improving diagnostic precision and treatment outcomes for UESL patients.