Lymphoblastic Leukemia With Mature B-Cell Phenotype in Infancy

Area of Science:

• Pediatric Oncology
• Hematologic Malignancies
• Molecular Genetics

Background:

• Lymphoblastic leukemia with mature B-cell phenotype and specific blast morphology (L1/L2) is uncommon.
• Rearrangements of the mixed lineage leukemia (MLL) gene are associated with poor prognosis in infant lymphoblastic leukemia.
• MLL rearrangements in mature B-cell lymphoblastic leukemia are exceptionally rare.

Purpose of the Study:

• To describe a rare case of infant lymphoblastic leukemia with MLL rearrangement and mature B-cell phenotype.
• To analyze the clinical, genetic, and immunophenotypic characteristics of this rare presentation.
• To contextualize these findings within existing literature on MLL-rearranged infant leukemias.

Main Methods:

• Case report of an infant diagnosed with lymphoblastic leukemia.
• Immunophenotypic analysis to determine B-cell lineage and blast morphology.
• Genetic analysis to identify MLL gene rearrangements.

Main Results:

• The infant presented with lymphoblastic leukemia exhibiting surface immunoglobulin light chain expression and L1/L2 blast morphology.
• Genetic analysis confirmed a mixed lineage leukemia (MLL) gene rearrangement.
• The case represents a rare combination of mature B-cell phenotype, specific cytomorphology, and MLL rearrangement in an infant.

Conclusions:

• This case underscores the rarity of MLL-rearranged mature B-cell lymphoblastic leukemia in infants.
• The presence of MLL rearrangements in this context may indicate a poor prognosis.
• Further research is needed to understand the implications of MLL rearrangements in diverse lymphoblastic leukemia subtypes.