60 yrs female with core biopsy (not sufficient for full IH) and subsequent whole node biopsy (submandibular).  
PET scan: suspition for nasopharyngeal tumor, neck lymphadenopathy. Peripheral blood: NS.  
 
HISTO:  
- 60% diffuse and heterogenous blastic infiltrate (DLBCL);  
- The rest of: small lymphos zones with scattered small medium strongly Bcl2+ neo cells with the same IH and focally retained follicular structures with giant hyperlobated cells with "interstitial" infiltration pattern (FL?).  
 
IH (In sum)(DLBCL)(ABC/nonGCB): CD20/Pax5+; Bcl6/Mum1+; CD10/CD23(-); Bcl2+; CMYC+ 80% (IH "double"); CD5/CD21/CyclinD 1(-); IgM+; Ig lambda+ (restricton); IgD(-); Ki67 up to 80%.  
 
DIAGNOSIS: DLBCL, transformed ffrom FL (grade 3b?).  
SPECIAL QUESTs:  
1. Transformation vs DLBCL with folliculothropism?  
2. Grading of FL, when predominant "blasts" with hyperlobated polymorphic nuclei?  
 
Thank you beeing together.