Splenic EBV-positive inflammatory follicular dendritic cell sarcoma:a clinicopathological analysis and review of literature

LIU Wei; DENG Xiaoyu; ZHAO Chun

doi:10.3969/j.issn.1007-8096.2025.07.0016

Abstract：Objective To investigate the pathological characteristics,immunohistochemical phenotype,key points of diagnosis and differential diagnosis of EBV-positive inflammatory follicular dendritic cell sarcoma(EBV+IFDCS),aimed to improve the accuracy of its diagnosis,and figure out its treatment and prognosis.Methods The clinical history and pathological characteristics of two patients with EBV+FDC were retrospectively analyzed,immunohistochemistry and EBER in situ hybridization were used to assist in diagnosis,and relevant literatures were reviewed.Results The onset of the tumors in both cases was insidious,but revealed in physical examination or admission examination.Their average age was 57 years.Pathological characteristics included that the tumor was clearly demarcated from the surrounding spleen;a large number of lymphocytes,plasma cells,eosinophils and neutrophils were seen in the background,in which the fusiform cells were distributed in bundle or storiform or scattered,the cytoplasm was rich and lightly stained,the nucleus was oval,vacuole-shaped,the nuclear membrane was thin and clear,small nucleoli was visible,and the nuclear division was not easy to see;Epithelial granulomas may also be seen.Immunohistochemistry showed that fusiform cells expressed follicular dendritic cell markers CD21,CD35,and CD23.EBER was detected by in situ hybridization.Ki67 showed a low value-added index.Conclusion Spleen EBV+FDCS is a rare low-grade malignant tumor,which is related to EBV infection,and is easily misdiagnosed and missed due to various background cell types.Thus,it shall be diagnosed in combination with immunohistochemistry and EBER.It shall also be distinguished from IgG4-related disease,inflammatory myofibroblast tumors,lymphoma,etc.At present,its main treatment is surgical resection.