Abstract
Background
Chronic lymphocytic leukemia (CLL) is a clonal disorder of B lymphocytes, characterized by proliferation of small mature lymphocytes involving the blood, bone marrow, and lymphoid tissues. CLL can rarely involve the central nervous system (CNS), either by involving brain parenchyma or cerebrospinal fluid (CSF). We present a series of three cases with clinically significant involvement of the CNS with CLL.
Results
During the past 2 years, our medical center managed three patients with CLL who presented with symptomatic CNS involvement, as determined by flow cytometry. The immunophenotypic profile was that of a typical CLL with light chain restricted small B cells positive for CD20 (dim) and coexpressing CD5 and CD23. In addition, two patients had brain involvement by SLL that was confirmed by brain biopsy. Notably, the brain lesions had a mildly elevated Ki-67 proliferative index (10%-30%). Bone marrow was involved in two patients, showing nodular, interstitial, and diffuse patterns. Bone marrow involvement ranged from 60% to 80% and showed very low Ki-67 proliferative index. None of the patients had features suggestive of a CLL transformation. FISH was performed on either bone marrow or CSF and demonstrated that patient 1 had Del11q(ATM) and Dell13q, patient 2 had trisomy 12, and patient 3 had del17(TP53) and IGH rearrangement. All of the patients showed persistent CSF involvement, ranging from 4 to 12 weeks, requiring aggressive treatment with intrathecal chemotherapy. At the end of treatment, all of the patients were clear of CNS involvement as judged by flow cytometry of CSF.
Conclusion
We report three patients who had persistent involvement of CSF. Only one patient had del17(TP53), a cytogenetic feature that is associated with high-risk CLL. It would be interesting to study clonal evolution of CLL to understand the mechanisms that underlie involvement of the CNS.
Molecular and immunologic analysis of a chronic lymphocytic leukemia case with antibodies against human T-cell leukemia virus