Secondary follicular lymphoma of the bone, transformed into large cell lymphoma, in a patient with chronic lymphocytic leukaemia: an uncommon manifestation of Richter's syndrome.

Patients with chronic lymphocytic leukemia (CLL) are at a significantly increased risk of developing a second malignant neoplasm in the course of their disease. The occurrence of large cell lymphoma [Richter's syndrome (RS)] has been described in approximately 3-5% of CLL patients. Other types of secondary lymphoid malignancies are extremely rare. Here we describe a patient, heavily pretreated, with long history of CLL who developed a secondary follicular lymphoma, transformed into a diffuse large cell lymphoma (LCL), with isolated manifestation in the bone, a very rare manifestation of RS. CLL and LCL cells were of distinct clonal origin, as documented by DNA sequencing of the CDR3 regions. Twelve months after the completion of chemo- and local radiotherapy, the patient is still in remission.