50yrs old male with veryfied hairy cell leukaemia (DBA44+CD20+ CD5/CD23/Cyclin(-) infiltration in BM 90%). Suprclavicular lymph node was biopsied.  
HISTO/DIAGNOSIS: Architecture diffuselly obscured. Necrotic lymphadenitis with leucocytoclasia. Lymphoplasmacytic and eosinophilic capsular infiltration. Some epithelioid macrophages in clusters. some perinecrotic histyocytic reaction (granuloma like). some necrotic areas "sinus like", Grocott, Ziehl Neelsen, PAS stains are negative.  
IH: Ki67 high; Ig kappa/lambda~ 2/1; EBV ratio 2/1; LMP1+ CMV+ elements are absent; T zones are predominant; CD68/MPO+ crescentic histiocytes are absent; CD4/CD. CD138+ plsmacytes, esp. in pericapsular/perisinusoidal location. HCL (DBA44) (-).  
 
QUESTION: Origin of this necrotic lymphadenitis (virus? oth.?).  
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