Purpose To investigate the clinical,imaging,and pathological features of Kikuchi-Fujimoto disease(KFD).Methods A retrospective analysis was conducted on 123 pathologically confirmed KFD cases.Clinical and imaging data were collected,and histopathological features were evaluated using HE staining,immunohistochemistry,in situ hybridization for EBER,and molecular analyses(TCR/Ig gene rearrangements by PCR with capillary electro-phoresis).Results Among the 123 patients,the male-to-female ratio was 1∶2,with a median age of 30 years.All patients presented with lymphadenopathy.Among 30 hospitalized patients,63.3％(19/30)had fever,and 23.3％(7/30)had concurrent autoimmune diseases.Of the 12 patients who underwent PET-CT,91.7％(11/12)were sus-pected of malignancy,prompting biopsy recommendations.Among 47 consultation cases,27.7％(13/47)were ini-tially misdiagnosed as lymphoma.Histopathological examination revealed proliferative,necrotic,and xanthomatous phases,which coexisted or occurred independently.The proliferative phase was characterized by atypical lymphocytes and histiocytes,the necrotic phase by abundant eosinophilic fibrin deposits and nuclear debris,and the xanthomatous phase by clusters of foam-like histiocytes.Immunohistochemically analyses revealed that atypical lymphocytes were neg-ative for CD20,CD4,and CD56 but positive for CD3,CD8,TIA1,Granzyme B,and Perforin.Histiocytes expressed CD68,CD163,and MPO,while CD123-positive plasmacytoid dendritic cells were predominantly located around the le-sions and blood vessels.EBER was positive in individual cells in 4 cases.TCR gene rearrangement was positive in 2 cases and suspected positive in 3 cases,while Ig rearrangement was positive and suspected positive in 1 case each.Conclusion KFD exhibits clinical,imaging,and pathological features that can mimic lymphoma,highlighting the im-portance of accurate diagnosis to avoid misdiagnosis and inappropriate treatment.

Purpose To investigate the clinical,imaging,and pathological features of Kikuchi-Fujimoto disease(KFD).Methods A retrospective analysis was conducted on 123 pathologically confirmed KFD cases.Clinical and imaging data were collected,and histopathological features were evaluated using HE staining,immunohistochemistry,in situ hybridization for EBER,and molecular analyses(TCR/Ig gene rearrangements by PCR with capillary electro-phoresis).Results Among the 123 patients,the male-to-female ratio was 1∶2,with a median age of 30 years.All patients presented with lymphadenopathy.Among 30 hospitalized patients,63.3％(19/30)had fever,and 23.3％(7/30)had concurrent autoimmune diseases.Of the 12 patients who underwent PET-CT,91.7％(11/12)were sus-pected of malignancy,prompting biopsy recommendations.Among 47 consultation cases,27.7％(13/47)were ini-tially misdiagnosed as lymphoma.Histopathological examination revealed proliferative,necrotic,and xanthomatous phases,which coexisted or occurred independently.The proliferative phase was characterized by atypical lymphocytes and histiocytes,the necrotic phase by abundant eosinophilic fibrin deposits and nuclear debris,and the xanthomatous phase by clusters of foam-like histiocytes.Immunohistochemically analyses revealed that atypical lymphocytes were neg-ative for CD20,CD4,and CD56 but positive for CD3,CD8,TIA1,Granzyme B,and Perforin.Histiocytes expressed CD68,CD163,and MPO,while CD123-positive plasmacytoid dendritic cells were predominantly located around the le-sions and blood vessels.EBER was positive in individual cells in 4 cases.TCR gene rearrangement was positive in 2 cases and suspected positive in 3 cases,while Ig rearrangement was positive and suspected positive in 1 case each.Conclusion KFD exhibits clinical,imaging,and pathological features that can mimic lymphoma,highlighting the im-portance of accurate diagnosis to avoid misdiagnosis and inappropriate treatment.