Erythroleukemia relapsing as precursor B-cell lymphoblastic leukemia.

Area of Science:

• Hematology
• Oncology
• Molecular Biology

Background:

• Acute myeloid leukemia (AML) with erythroid differentiation (erythroleukemia) is a subtype with distinct characteristics.
• Relapse of AML as acute lymphoblastic leukemia (ALL) is uncommon.
• Complex karyotypic abnormalities, such as monosomy 5 and 7, are associated with poor prognosis in myeloid leukemias.

Observation:

• A 62-year-old man with erythroleukemia and complex karyotype achieved remission with chemotherapy.
• He relapsed 4 months later with precursor B-cell ALL, exhibiting different morphology and immunophenotype.
• Bone marrow analysis revealed the same leukemic clones and complex karyotypic abnormalities (monosomy 5 and 7) as the primary erythroleukemia.

Findings:

• The relapsing precursor B-cell ALL shared the same leukemic clones as the initial erythroleukemia.
• This case represents the first documented instance of a lineage switch from erythroleukemia to ALL.
• The findings highlight the potential for significant clonal evolution and lineage plasticity in leukemia.

Implications:

• This case expands the understanding of leukemia's complex behavior and potential for lineage plasticity.
• It underscores the importance of comprehensive immunophenotypic and cytogenetic analysis at relapse.
• Further research into the mechanisms driving such lineage switches may offer novel therapeutic targets for relapsed leukemia.