Biclonal B-cell chronic lymphocytic leukemia with inv(14)(q11q32)

Biclonal lymphoproliferative disorders: another association with NOTCH1-mutated chronic lymphocytic leukaemias

INTRODUCTION

Biclonal lymphoid disorders, when two distinct lymphoproliferative disorders (LPD) co-exist, are rare (incidence of 1.4%) and associated with a poor prognosis. NOTCH1 mutations occur in 10% of CLL at diagnosis, associated with a short disease-free interval and increased risk of Richter's transformation. We hypothesised that the incidence of NOTCH1 mutations in CLL with a second LPD may be increased, because the mutation occurs early in leukaemogenesis, permitting clonal divergence.

METHODS

We identified 19 patients with biclonal LPD at diagnosis: 11 with CLL and a second LPD (group A) and 8 with a second distinct CLL (group B). NOTCH1 mutation analysis was performed and clinical outcome investigated.

RESULTS

Ten of 19 (52%) were NOTCH1 mutated: 5 in group A (45%) and 5 in group B (62.5%) with a favourable clinical outcome observed among this cohort with 28.7 (range 1-99) months of follow-up.

CONCLUSION

In conclusion, we identified a significant (52%) incidence of NOTCH1 mutations in CLL in the context of biclonal LPD, associated with an indolent clinical course.

Guess what: Chronic 13q14.3+/CD5-/CD23+ lymphocytic leukemia in blood and t(11;14)(q13;q32)+/CD5+/CD23- mantle cell lymphoma in lymph nodes!

We report a case of a patient with two B-cell lymphoproliferative disorders: CD5(-)/CD23(+) B-cell chronic lymphocytic leukemia and CD5(+)/CD23(-) mantle cell lymphoma. These disorders were diagnosed simultaneously based on flow cytometry, immunohistochemistry, fluorescence in situ hybridization, and polymerase chain reaction-based molecular studies. The B-cell lymphocytic leukemia clone predominated in the blood and bone marrow, whereas the mantle cell clone predominated in lymph nodes.

Biclonal chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is well characterized clinically and immunophenotypically. Demonstration of a monotypic CD19+, CD5+ B-cell population is central to the diagnosis. We report 2 cases of biclonal CLL. Two elderly men were encountered with an absolute lymphocytosis consisting of the typical CD5+, CD19+, CD23+ B-cell population seen in CLL; however, immunoglobulin light chain restriction by flow cytometry was not apparent as B cells expressed kappa or lambda light chains without a clear monotypic population. Molecular genetic analysis of flow cytometry-sorted cells (kappa and lambda populations) revealed in both cases 2 monoclonal B-cell populations. The characterization of these cases and a review of the issues surrounding biclonal CLL are presented.

Cytogenetic triclonality in T-cell acute lymphoblastic leukemia: a conventional and molecular cytogenetic study

Cytogenetically-unrelated clones are infrequently seen in hematologic malignancies, and are particularly uncommon in acute lymphoblastic leukemia. We report a case of T-cell acute lymphoblastic leukemia with L2 morphology which demonstrated three cytogenetically distinct clones: 46,XY,t(2;9)(p21;q34)/46,XY,del(6)(q21q23)/47,XX,+8. Interphase cytogenetic analysis by fluorescence in situ hybridization (FISH) confirmed the presence of trisomy 8 in a significant proportion of lymphoblasts, while reverse transcription-polymerase chain reaction (RT-PCR) did not show the presence of BCR/ABL fusion. This is the first report describing the occurrence of cytogenetic triclonality in de novo T-cell acute lymphoblastic leukemia.

Cytogenetic abnormalities in chronic B-cell lymphoproliferative disorders in Chinese patients

We analyzed the cytogenetic findings of 59 Chinese patients with chronic B-cell lymphoproliferative disorders. More than half of the patients (n = 36, 61%) had chronic lymphocytic leukemia. Cytogenetic abnormalities were demonstrated in 44.1% (26/59) of the patients. Trisomy 12 was the most frequent abnormality in chronic lymphocytic leukemia and was found in 27.8% (10/36) of the patients, indicating that the incidence of trisomy 12 in chronic lymphocytic leukemia in Chinese patients might not be low compared with the West as previously suggested. Structural abnormalities involving chromosomes 13 at band q14 were the next most common abnormalities in patients with chronic lymphocytic leukemia. Among the 11 patients with mantle cell lymphoma in leukemic phase, t(11;14) was seen in only 2 patients (18.2%). Several unusual cytogenetic abnormalities also were found.