Based on immunophenotypic grounds, MBL can be classified as chronic lymphocytic leukaemia (CLL)-like MBL, with a CD5+, CD23+ and CD20low phenotype representing the most common subgroup (∼ 75/80% of MBL), atypical-CLL (CD5+, CD20bright) and CD5− MBL [2]. Here, CD5 is linked to B-cell chronic lymphocytic leukemia.