Synchronous Undifferentiated Embryonal Sarcoma of the Liver and Fibrolamellar Hepatocellular Carcinoma in a Patient with Adenosine Deaminase Deficiency

Adenosine deaminase deficiency causes severe combined immunodeficiency, affecting T and B cells and increasing the risk of infections, immune dysregulation, and malignancy. Undifferentiated embryonal sarcoma of the liver is a rare pediatric mesenchymal tumor. We report a 7-year-old boy with adenosine deaminase deficiency presenting with fever, elevated acute phase reactants, and an 85 × 60 mm² heterogeneous cystic liver mass on ultrasonography. Magnetic resonance imaging revealed a second nodule in segments 5 and 6. An abscess was initially suspected, but biopsy confirmed undifferentiated embryonal sarcoma of the liver. After chemotherapy, the patient underwent a left lobectomy and wedge resections. Histology showed complete necrosis of the sarcoma; however, a second tumor—fibrolamellar hepatocellular carcinoma—was identified. While immunodeficiencies are associated with lymphoproliferative disorders and malignancies, the link between adenosine deaminase deficiency and hepatic tumors is unclear. This patient's presentation highlights the potential for multiple primary hepatic malignancies in immunodeficient patients and suggests a need for further investigation.