MANTLE CELL LYMPHOMA - A MORPHOLOGICAL, IMMUNOHISTOCHEMICAL AND MOLECULAR-GENETIC STUDY

In order to identify helpful markers in the classification of mantle c ell lymphoma, a morphological, immunohistochemical and molecular genet ic analysis of 41 cases of NHL, originally referred to us as CC, ILL o r LDL, was performed. We revised these lymphomas using the strict morp hological criteria described in the updated Kiel classification and th e more recently described criteria for MCL. The term MCL was used to d esignate the small lymphocytic B-cell NHL, previously referred to as C C or ILL/IDL. This revision yielded 20 MCL, 8 CLL, 3 Cb/Cc, 1 CB, 6 JC and 3 MALT lymphomas. The presence of scattered histiocytes was seen in 90% of MCL and 5% of the other cases. No other morphological parame ter besides the used criteria, differentiated between MCL and similar small lymphocytic B cell lymphomas. Helpful immunohistochemical marker s to distinguish MCL from similar small lymphocytic lymphomas were CD5 +, CD10 -, CD23 - and Alkaline Phosphatase +. Large fields of dendrit ic reticulum cells, often in a loose and disrupted arrangement were se en in 82% of MCL and in 19% of the other lymphomas. Analysis with Sout hern blotting showed a rearrangement in the BCL-1 locus in 12/20 cases of MCL but not in the other 21 lymphomas. Although very specific for MCL, Southern blotting to detect BCL-1 rearrangements is, due to the l arge number of probes necessary, not of great help in daily practice f or routine diagnostic purposes. We conclude that using strict morpholo gical criteria, the diagnosis MCL can be made reliably and that immuno phenotyping is helpful in supporting the diagnosis.