54 yrs male with clin. dgn.:"lymphoma".  
SESSION 1: Threpine biopsy was performed.  
BM HISTO: In NASDE slides some central and peritrabdecular lymphoid infiltrates are obvious.  
IH: Infiltrates CD20>>CD3 (reactivity od CD3 is low!); CD30+ cells are absent. Ki67 is very low (single cells +).  
PROPOSAL: B lymphoid infiltration, highly supspitious for NHL (low grade?)?  
SESSION 2:  
L/N HISTO: Diffuse infiltration (WITH SOME NODULARITY- dr.A.Orazzi note) of medium- large sized cells with high proliferative activity, bluish cytoplasm, pleomorphic nuclei with CB and IB like morphology. Single Eo's, plasma cells and prominent admixture of T lympho's (CD5/CD3+) are present.  
L/N IH: Large "blasts": CD20 (+), Ki 67 (+) up to 70%, MUM 1/BCL-6(+) 5-10%, Bcl2 (+)30% (admixture of Bcl2+ lymphos), CD30/EBV LMP1/CD34/TDT(-), CyclinD1(-)(single nuclei, most probably histyocytic, +). The single plasmacytes (CD138+).  
PROPOSAL: DLBCL vs ...?  
SPECIAL QUESTIONS: 1. Low Mum1/Bcl6+ fraction as for DLBCL? 2. BM interpretation in the light of LN data.  
Molecular monoclonality studies are pending on L/N.  
THANK YOU FOR YOUR PATIENCE AND HELP.