A Rare Case of EBV-positive Inflammatory Follicular Dendritic Cell Sarcoma of the Iliac Bone

Epstein-Barr virus (EBV) has been shown to be associated with the occurrence of certain types of malignant tumors, including EBV-positive (EBV+) inflammatory follicular dendritic cell sarcoma (FDCS) and nasopharyngeal carcinoma (NPC). In this case study, we present the diagnosis of a Chinese male who sequentially developed iliac bone-derived EBV + inflammatory FDCS and NPC, both of which were associated with EBV. The diagnosis was confirmed through positive immunohistochemical staining for specific markers of EBV + inflammatory FDCS (CD21, CD23, CD35 and CXCL13) and in situ hybridization of EBV encoding RNA (EBER). Furthermore, Next-generation Sequencing (NGS) identified copy number amplification of CCND1 and FGF19, as well as copy number loss of CDKN2A and CDKN2B. These genetic alterations may partially account for patient’s unfavorable prognosis, as evidenced by local recurrence at the 3rd month post-surgery and subsequent death at the 4th month post-surgery. This case suggests that a patient may develop multiple types of EBV-related cancers, which could feature unfavorable outcome as indicated by the NGS results.