Richter's syndrome (RS), also known as Richter's transformation, is a transformation which occurs in about 5-10% of B cell chronic lymphocytic leukemia (CLL) and hairy cell leukemia into a fast-growing diffuse large B cell lymphoma, a variety of non-Hodgkin lymphoma which is refractory to treatment and carries a bad prognosis. There is also a less common variant in which the CLL changes into a Hodgkin's lymphoma. Rarely, transformations to a form of myeloid leukemia have been observed. These extraordinarily rare transformations carry a very poor prognosis.
Richter's transformation affects about 5% of CLL patients at some point during their lives.
Signs and symptoms
Symptoms of Richter’s transformation in a CLL patient include fever (without infection), an elevated serum levels of lactate dehydrogenase, and rapidly enlarging lymph nodes. While about 8% of all CLL patients will have elevated levels of serum lactate dehydrogenase (LDH), more than 50% of CLL patients with Richter's transformation will have elevated LDH levels.
Richter's can appear suddenly, even in patients who were in remission.
A case of RS may have arisen by one of two different routes: a transformation of the CLL cells into lymphoma, or the appearance of an unrelated lymphoma.
It is thought that genetic defects may introduce the additional abnormalities necessary to transform CLL cells into Richter's syndrome cells.
Treatment with conventional immunochemotherapy is usually indicated; in younger patients, allogeneic bone marrow transplantation may be curative.
The prognosis is generally poor. The "RS score" (Richter syndrome score), which is an estimate of the patient's prognosis, is based on the patient's performance status, LDH, platelet count, the size of the lymphoma tumors, and the number of prior therapies already received. Overall, the median survival is between five and eight months. Untreated, RS is invariably fatal.
The Hodgkin's lymphoma variant of Richter's carries a better prognosis than the predominant diffuse large B-cell lymphoma type, but a worse prognosis than a "de novo" case of Hodgkin's.
In the United States, about 500 patients are diagnosed with Richter's transformation each year.