38 yrs old male with hyperglobulinemia (esp. IgM), hepatosplenomegaly underwent threpine biopsy.  
HISTO: The prominenet infiltration of macrofages, focal serous degeneration, architectural abnormalities, erythroid hyperplasia. Definite features of hemophagocytosis are absent. The single mixed B/T (reactive) peritrabecullar follicle is present. Intersticial lymhoid population: CD3+ > CD20+ (reactive).  
CLIN DIAGNOSIS: Waldenstrom disease (LPL)???  
IH: Nothing special. The single CD117+ mastocytes. Ig kappa/lambda monotypic.  
PAS staining (not standard in our BMs) is in progress.  
 
PROPOSAL: Reactive changes: the prominent macrophageal reaction in BM: hemophagocytosis? Virus induced? Etc.?  
 
Thank you fo being 2gether.