Epstein-Barr Virus-Positive Inflammatory Follicular Dendritic Cell Sarcoma of the Liver: A Rare Case with Genomic Profiling and Therapeutic Implications

Hepatic Epstein-Barr virus-positive inflammatory follicular dendritic cell sarcoma (EBV + IFDCS) is an extremely rare low-grade malignant tumor. We report a case of a 50-year-old woman misdiagnosed preoperatively with hepatocellular carcinoma (HCC) due to overlapping imaging features. Postoperative histopathology, immunohistochemistry (CD21/CD23/CXCL13 positivity), and Epstein-Barr virus-encoded RNA (EBER) in situ hybridization confirmed EBV + IFDCS. Genetic profiling revealed low tumor mutational burden (TMB: 2.36 Muts/Mb), microsatellite instability (MSI: 1.9%), and absence of targetable mutations, suggesting poor sensitivity to immunotherapy and targeted therapy, but potential responsiveness to chemotherapy (e.g., Tegafur/Gimeracil/Oteracil). This case highlights the diagnostic challenges, therapeutic implications of genetic testing, and the need for standardized multidisciplinary approaches for this rare entity.