Richter's syndrome following cladribine therapy for chronic lymphocytic leukemia first manifested as pathologic fracture of the femur

Richter's syndrome (RS) refers to the development of aggressive non-Hodgkin 's lymphoma (NEL) during the course of chronic lymphocytic leukaemia (CCL). It occurs in approximately 3% of patients with CLL. The isolated form of t his complication in bone is extremely rare and, so far, has not been descri bed in a patient treated with cladribine (2-CdA). We report a case of CLL t reated successfully with 2-CdA, where isolated diffuse large B-cell lymphom a (LBCL) developed 2 years after the diagnosis of CLL Rai II and one year a fter the completion of 2-CdA treatment. RS was first manifested as a pathol ogic fracture of the left femur. The LBCL was clonally distinct from the or iginal CLL cells. The patient was successfully treated with CHOP and radiot herapy and obtained complete response of the LBCL.