Novel identification of t(14;18)(q32;q21)/IGH::MALT1 in chronic lymphocytic leukaemia

Summary Chronic lymphocytic leukaemia (CLL) is a clonal B‐cell malignancy and remains a chronic disease despite improvements in clinical outcomes since the use of targeted therapies. Both clinical and biological parameters are important for determining prognosis. Unlike other mature B‐cell lymphomas, translocations involving the immunoglobulin heavy chain ( IGH ) locus are uncommon in CLL. There have been few case reports of CLL harbouring t(14;18)/ IGH::BCL2 and t(14;19)/ IGH::BCL3 . Here we describe the first two cases of patients with CLL with documented t(14;18)(q32;q21)/ IGH::MALT1 . Both cases in this report were associated with lower‐risk biological parameters. Thus, FISH testing for MALT1 in cases with unknown IGH translocation partners in the setting of CLL should be implemented in clinical practice to better define such cases.