Long-Term Survival in an Adolescent and Young Adult with Metastatic Relapse of an Undifferentiated Embryonal Sarcoma of the Liver.

Undifferentiated embryonal sarcoma of the liver (UESL) is an extremely rare and aggressive malignancy in adults. Adults with UESL have a worse prognosis compared to pediatric population. Due to the rarity of this disease in adults, there has been a lack of information that assists in treatment decisions within this group. Improved understanding of UESL in adults might assist in understanding biological differences compared to pediatric cohorts as well as tailor treatments to improve their overall outcome. We described the management and outcome of a young adult managed at our center with metastatic relapsed UESL. For comparison, a PubMed search for adolescent and young adult (AYA) and adults with UESL was performed with the aim to review and address any distinct clinical features, different aspects of management and survival outcomes within this population. A 21-year-old male underwent right hepatectomy for a large 16 cm localized UESL with clear surgical margin and did not receive adjuvant chemotherapy. Seven months postsurgery, he relapsed with both local and metastatic disease and underwent chemotherapy with vincristine, doxorubicin, cyclophosphamide alternating with ifosfamide and etoposide achieving a complete metabolic response. This was followed by Stereotactic Ablative Radiation Therapy and surgical resection of residual disease. He remains free of disease 3 years since his diagnosis. We subsequently reviewed 42 AYA and adults (aged >15) with UESL (median age, 33 years) between 1991 and 2022. Most patients presented with localized UESL and for those treated with surgery alone, 67% developed recurrences. Those receiving multimodality treatment, better outcomes, and reduced relapse rate was achieved. Twenty-seven patients developed recurrences, 13 with local recurrences and 14 with metastatic relapse. The median time to relapse was 12 months. We reported a successful outcome in multimodality treatment which resulted in long remission in a young adult with relapsed UESL. Combination of perioperative chemotherapy with locoregional treatment is important to improve long-term survival in adults with metastatic UESL.