Document resource
Richter transformation (also known as Richter syndrome) is a well-known phenomenon in which patients with chronic lymphocytic leukaemia/small lymphocytic lymphoma (CLL/SLL) develop an aggressive lymphoma, usually diffuse large B-cell lymphoma (DLBCL) and uncommonly classic Hodgkin lymphoma.1 The prevalence rate of Richter transformation in CLL/SLL patients ranges from 1% to 23%, depending on the study population and inclusion criteria.2 The prognosis of DLBCL-type Richter transformation is dismal. One of the most important prognostic factors is the clonal relationship between the CLL/SLL and DLBCL tumours. Cases of DLBCL-type Richter transformation that are clonally related to the CLL/SLL carry a worse prognosis, whereas clonally unrelated DLBCL cases have a prognosis similar to that in de novo DLBCL.3