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The monoclonal B-cell lymphocytoses (MBLs) introduced as new entities in the 2008 WHO classification are defined by a circulating B-cell clone &lt: 5.109/L without organomegaly and previous and/or simultaneous lymphoproliferative disorders. The MBLs were subclassified into MBL CLL type (the most common), MBL atypical CLL type, and MBL non-CLL type (rarely reported in the literature). Here the clinical, cytological, immunological, and genetic features of MBL non-CLL type have been described using a series of 34 cases. As previously reported, present cases presented immunological and genetic similarities to marginal zone lymphoma (MZL) and could be associated with the new proposed entity CBL-MZ (clonal B-cell lymphocytosis of marginal zone origin). In addition, a few cases presented similarities to splenic diffuse red pulp small B-cell lymphoma (SDRPL). In conclusion, according to the literature, MBL with non-CLL type (assimilated to CBL-MZ) may be a premalignant state of MZL and/or SDRPL.