Richter transformation is defined as a transformation of CLL into an aggressive lymphoma, most commonly diffuse large B-cell lymphoma. Less commonly (in about 10% of cases - Jamroziak K et al. 2015) into Hodgkin's lymphoma, referred to as Hodgkin variant Richter syndrome (HvRS).
The patients with Richter transformation usually respond poorly to conventional chemotherapy used to treat diffuse large B-cell lymphoma de novo.
The incidence of Richter transformation is reported between 4% to 20% of previously treated CLL patients (Ding W 2018).
Patients show a rapid clinical deterioration. In particular, a rapid increase in B-symptomatology is observed. This is a rather rarely observed phenomenon in CLL. Furthermore, localized or generalized lymph node swelling and an increase in the LDH value are indicative.
Histopathological examination is a prerequisite for diagnosis. It is crucial to assess the relationship between the RS clone and the underlying CLL/SLL, as clonally related DLBCL-RS have a poor prognosis, while clonally unrelated cases have a similar prognosis to de novo DLBCL.
Immunochemotherapy based on anti-CD20 antibodies has been the first choice in the treatment of DLBCL-RS (see CLL below); however, the results are not satisfactory (Puła B et al. 2019). Younger and fit patients should be offered allogeneic stem cell transplantation as consolidation therapy.
Patients with Richter transformation have a significantly worse prognosis than most patients with CLL. This probably results from an unfavourable individual genetic mutation pattern.