Burkitt-Type Acute Lymphoblastic Leukemia With Precursor B-Cell Immunophenotype and Partial Tetrasomy of 1q: A Case Report

Emerging entities: high-grade/large B-cell lymphoma with 11q aberration, large B-cell lymphoma with IRF4 rearrangement, and new molecular subgroups in large B-cell lymphomas. A report of the 2022 EA4HP/SH lymphoma workshop

Emerging entities and molecular subgroups in large B-cell lymphomas (LBCLs) were discussed during the 2022 European Association for Haematopathology/Society for Hematopathology workshop in Florence, Italy. This session focused on newly recognized diseases and their diagnostic challenges. High-grade/large B-cell lymphoma with 11q aberration (HG/LBCL-11q) is defined by chromosome 11q-gains and telomeric loss. FISH analysis is recommended for the diagnosis. HG/LBCL-11q can occur in the setting of immunodeficiency, including ataxia-telangiectasia, and predominates in children. The morphological spectrum of these cases is broader than previously thought with often Burkitt-like morphology and coarse apoptotic bodies. It has a Burkitt-like immunophenotype (CD10+, BCL6+, BCL2-) but MYC expression is weak or negative, lacks MYC rearrangement, and is in contrast to Burkitt lymphoma 50% of the cases express LMO2. LBCL with IRF4 rearrangement (LBCL-IRF4) occurs mainly in the pediatric population but also in adults. LBCL-IRF4 has an excellent prognosis, with distinguishing molecular findings. IRF4 rearrangements, although characteristic of this entity, are not specific and can be found in association with other chromosomal translocations in other large B-cell lymphomas. Other molecular subgroups discussed included primary bone diffuse large B-cell lymphoma (PB-DLBCL), which has distinctive clinical presentation and molecular findings, and B-acute lymphoblastic leukemia (B-ALL) with IGH::MYC translocation recently segregated from Burkitt lymphoma with TdT expression. This latter disorder has molecular features of precursor B-cells, often tetrasomy 1q and recurrent NRAS and KRAS mutations. In this report, novel findings, recommendations for diagnosis, open questions, and diagnostic challenges raised by the cases submitted to the workshop will be discussed.

Molecular characterization and clinical outcome of B-cell precursor acute lymphoblastic leukemia with IG-MYC rearrangement

Rarely, immunophenotypically immature B-cell precursor acute lymphoblastic leukemia (BCP-ALL) carries an immunoglobulin- MYC rearrangement (IG-MYC-r). This can result in diagnostic confusion with Burkitt lymphoma/leukemia and use of individualized treatment schedules of unproven efficacy. Here we compare the molecular characteristics of these conditions and investigate historic clinical outcome data. We identified 90 cases registered in a national BCP-ALL clinical trial/registry. When present, diagnostic material underwent cytogenetic, exome, methylome and transcriptome analyses. The outcomes analyzed were 3-year event-free survival and overall survival. IG-MYC-r was identified in diverse cytogenetic backgrounds, co-existing with either established BCP-ALL-specific abnormalities (high hyperdiploidy, n=3; KMT2A-rearrangement, n=6; iAMP21, n=1; BCR-ABL1, n=1); BCL2/BCL6-rearrangements (n=15); or, most commonly, as the only defining feature (n=64). Within this final group, precursor-like V(D)J breakpoints predominated (8/9) and KRAS mutations were common (5/11). DNA methylation identified a cluster of V(D)J-rearranged cases, clearly distinct from Burkitt leukemia/lymphoma. Children with IG-MYC-r within that subgroup had a 3-year event-free survival of 47% and overall survival of 60%, representing a high-risk BCP-ALL. To develop effective management strategies this group of patients must be allowed access to contemporary, minimal residual disease-adapted, prospective clinical trial protocols.

Acute Lymphoblastic Leukemia Transformation with a Precursor B-Cell Immunophenotype to Burkitt's Lymphoma: a Case Report

Background

As a new point, some very rare features can be revealed as initial diagnosis of acute lymphoblastic leukemia (ALL) without any evidence of lymphoma-like behavior which after initial recovery, presents with new evidence of lymphoma. Herein, a case of the immunophenotypes of blast cells in B-cell precursor acute lymphoblastic leukemia originated from MYC gene-related that was evidenced later by burkitt lymphoma feature.

Case Presentation

Our case was initially diagnosed as a typical B-cell ALL cells with L1 morphology in peripheral blood smear and bone marrow aspiration that was not recovered and referred again that was finally featured as burkitt's lymphoma with L3 morphological feature.

Conclusion

Thus, in the primary diagnosis of B-cell ALL and especially in cases with treatment failure, the final feature of burkitt's lymphoma should be potentially in mind.

Nationwide study of pediatric B-cell precursor acute lymphoblastic leukemia with chromosome 8q24/MYC rearrangement in Japan

BACKGROUND

Rearrangements of chromosome 8q24/MYC (8q24/MYC-r), resulting from t(8;14)(q24;q32), t(2;8)(p11;q24), or t(8;22)(q24;q11), are mainly associated with Burkitt lymphoma/leukemia (BL) and rarely observed in patients with B-cell precursor acute lymphoblastic leukemia (BCP-ALL). The characteristics of BCP-ALL with 8q24/MYC-r are poorly understood.

PROCEDURE

A retrospective nationwide study of data from patients with pediatric BCP-ALL with 8q24/MYC-r in Japan was conducted to clarify the clinical and biological characteristics associated with 8q24/MYC-r BCP-ALL.

RESULTS

Ten patients with BCP-ALL with 8q24/MYC-r, including three with double-hit leukemia (DHL) (two with t(8;14)(q24;q32) and t(14;18)(q32;q21) and one with t(8;14) and t(3;22)(q27;q11)), were identified. Patients with BCP-ALL with 8q24/MYC-r had higher median age and uric acid and lactate dehydrogenase levels, than those without 8q24/MYC-r. All patients were initially treated with ALL-type chemotherapy; however, four, including one with DHL, were switched to BL-type chemotherapy, based on cytogenetic findings. One patient relapsed after standard-risk ALL-type chemotherapy, and two patients with DHL did not attain complete remission with chemotherapy; all three died within 11 months. The other seven patients treated with BL-type or high-risk ALL-type chemotherapy are alive without disease.

CONCLUSIONS

The clinical and laboratory features of BL with IG-MYC rearrangement, displaying a BCP immunophenotype (Wagener et al. and Herbrueggen et al. termed it as pre-BLL), are similar to those of BCP-ALL with 8q24/MYC-r. Low-risk ALL-type chemotherapy may not be appropriate for them, and further studies are required to establish an adequate therapeutic strategy. Further studies of DHL to identify new treatment strategies are also needed.

Burkitt Leukemia With Precursor B-Cell Immunophenotype and Dual Translocation of t(14;18) and t(8;14) in a Child: Case Report and Review of the Literature

BACKGROUND

Burkitt leukemia (BL) with the precursor B-cell immunophenotype is a rarely reported condition. The prognosis of such patients is similar to that of classic BL. However, the combination of chromosomal translocations associated with bcl-2 and c-myc rearrangement has a poor prognosis.

OBSERVATIONS

An 11-year-old child presented with fever and weakness. Bone marrow aspiration showed morphologically L1 type blasts and flow cytometry analysis was compatible with precursor B-cell immunophenotype. Cytogenetic analysis revealed a combination of t(8;14) and t(14;l8).

CONCLUSIONS

The combination of t(8;14) and t(14;l8) can exhibit different immunophenotypical and morphologic features in leukemias.

MLL rearranged acute lymphoblastic leukaemia presenting as a maxillary sinus mass with a discordant immunophenotypic profile from the bone marrow

We describe an unusual case of pre-B lymphoblastic leukaemia presenting with a unilateral maxillary sinus mass in which biopsies of the primary mass and the bone marrow demonstrated conflicting immunophenotyping results. The extramedullary mass was consistent with a precursor B-cell malignancy, while the bone marrow was initially reported as a possible mature B-cell malignancy. The treatments for the two are fundamentally different, which necessitated a delay in the initiation of his chemotherapy until a clear diagnosis was made. Mixed lineage leukaemia gene rearrangement was confirmed by fluorescence in situ hybridisation in both the primary mass and bone marrow, which unified the diagnosis as pre-B acute lymphoblastic leukaemia given the common cytogenetic feature.