RESUMEN
Purpose To explore the clinicopathologic fea-tures of Epstein-Barr virus-positive inflammatory follicular den-dritic cell sarcoma(EBV+IFDCS).Methods The clinico-pathologic features of 9 cases of EBV+IFDCS were retrospective-ly analyzed and followed up.Results The age of 9 patients with EBV+IFDCS ranged from 22 to 78 years(mean 44.7 years).7 cases occurred in the liver and 2 in the spleen.Fi-brinoid degeneration and hyaline degeneration in the vessel walls(6/9),eosinophilic infiltration(3/9),and epithelioid granulo-mas(2/9)were seen in some cases.The tumor cells expressed CD21(7/9),CD23(8/9)and CD35(9/9),partially ex-pressed SMA(6/9)and D2-40(1/9).It was noteworthy that 2 cases from the spleen accompanied by high expression of IgG4 plasma cells(80-135/10 HPF),and in the liver(0-36/10 HPF).All cases were followed up for 3-84 months,with 6 pa-tients disease-free,2 patients underwent metastasis,1 patient lost of follow-up.Conclusion EBV+IFDCS is a rare low-grade malignant tumor.EBER in situ hybridization and immunohisto-chemical detection play important roles in the diagnosis and dif-ferential diagnosis of EBV+IFDCS.Surgical resection is the main therapeutic intervention for EBV+IFDCS,and patients re-quire long-term post-surgical follow-up.