How do you distinguish benign from malignant extranodal small B-cell proliferations?

The diagnostic criteria for malignancy for small B-cell lymphoproliferative disorders in extranodal sites are controversial. However a multiparameter approach that integrates clinical features, morphologic features, phenotype , and genetics techniques allows for a confident separation of lymphomas fr om lymphoid hyperplasia in most cases. By morphologic features, formation o f a mass, tissue architectural effacement, cellular monomorphism, cytologic atypia, presence of proliferation centers, and plasma cells containing Dut cher bodies are all features of low-grade B-cell lymphomas. Demonstration o f immunoglobulin light chain restriction or of art aberrant B-cell phenotyp e are immunologic features that help to support a malignant diagnosis. Beca use of technical limitations and ambiguity regarding the significance of sm all B-cell clones, the roles of the Southern blot analysis and the polymera se chain reaction techniques to demonstrate clonal immunoglobulin gene rear rangements or various chromosomal translocations must be evaluated further as potential criteria for malignancy. As more molecular techniques are appl ied to low-grade B-cell lymphoproliferative disorders, more of the steps in lymphomagenesis are being defined, and the critical molecular events that predict adverse clinical outcome have yet to be discovered. Therefore, more studies are required to search for additional molecular markers that defin e adverse outcome so that the number of cases of borderline small B-cell ly mphoproliferative disorders can be minimized.