Richter transformation, historically called Richter syndrome, can affect patients who have or have not been treated for chronic lymphocytic leukemia (CLL). In rare cases, it can occur in previously untreated patients with CLL. 

Named after Maurice Richter, Ph.D., Richter transformation occurs when chronic lymphocytic leukemia changes into a more aggressive disease – usually diffuse large B-cell lymphoma or, much less commonly...