RT Journal Article SR Electronic T1 Sentinel case of Richter transformation from chronic lymphocytic leukaemia/small lymphocytic lymphoma to CD3+ diffuse large B-cell lymphoma JF Journal of Clinical Pathology JO J Clin Pathol FD BMJ Publishing Group Ltd and Association of Clinical Pathologists SP 575 OP 578 DO 10.1136/jclinpath-2016-204024 VO 70 IS 7 A1 Ali Ismail A1 Jawed A Mallick A1 Dahui Qin A1 Mohammad O Hussaini YR 2017 UL http://jcp.bmj.com/content/70/7/575.abstract AB Aim To report the first case of a Richter syndrome where small lymphocytic lymphoma (SLL) progressed to a CD3+ diffuse large B-cell lymphoma (DLBCL).Methods Macrodissection of small and large cell lymphomatous components was performed. This was followed by flow cytometric analysis along with molecular B-cell immunoglobulin (heavy and light chains) and T-cell receptor (γ and β chains) gene rearrangement studies to investigate a clonal relationship between the components.Results The immunophenotypic profile was similar between small and large cell components of the lymphoma by flow cytometry. Furthermore, shared clonal peaks were observed between both components based on molecular B-cell and T-cell receptor gene rearrangement studies, confirming a clonal relationship.Conclusions Chronic lymphocytic leukaemia/SLL may rarely undergo Richter transformation to a DLBCL demonstrating lineage infidelity. This is a potentially important diagnostic pitfall and such cases should not be confused with a de novo T-cell lymphoma.