High-grade T-cell lymphoma complicating B-cell chronic lymphocytic leukemia: an unusual manifestation of "Richter's syndrome".

Approximately 3% of patients with B-cell chronic lymphocytic leukemia (CLL) develop a high-grade large-cell lymphoma consistent with Richter's Syndrome. In most cases, these lymphomas are of B-cell origin and are believed to arise by clonal evolution from the CLL cells. We present a case of a patient with a 10-year history of B-CLL who developed an aggressive large-cell lymphoma, confirmed by immunophenotype to be of T-cell origin. We suggest that in patients with CLL, immunodysregulation can result in the proliferation of T cells, which may mutate and result in the development of a new malignant clone.