Leukemic phase of follicular lymphomas: an atypical presentation.

Follicular lymphomas (FLs) are frequent B-cell derived malignancies, generally demonstrating an indolent evolution. Although circulating FL cells may be detected by high-resolution analysis, bloodstream involvement by FL cells is unusual. We observed in 10 patients a leukemic phase of FL at the onset of the disease. Six of them had concomitant lymph node involvement and all of them required treatment at diagnosis due to a high tumor burden, whereas four patients had pure FL-cell leukemia, which was associated with a more indolent clinical outcome. The detection of a leukemic phase should therefore be studied as a potential prognosis marker in further studies.