TdT-Positive, SmIg-Negative B Precursor Cell Leukemia with Burkitt Morphology: A Case Report.

Area of Science:

• Hematology
• Oncology
• Immunology

Background:

• Acute lymphoblastic leukemia (ALL) is a heterogeneous lymphoid malignancy.
• FAB-L3 morphology is a subtype of ALL, often associated with specific genetic abnormalities.
• B-cell precursor ALL represents a significant proportion of ALL cases.

Purpose of the Study:

• To describe the phenotypic marker profile and molecular analysis of a rare case of ALL with FAB-L3 morphology.
• To characterize the immunophenotype and genotype of leukemic cells in this unique patient.

Main Methods:

• Immunophenotyping using flow cytometry to detect B cell-associated antigens and terminal deoxynucleotidyl transferase (TdT).
• Molecular analysis of immunoglobulin heavy chain and T cell β-receptor genes.
• Cytogenetic investigation including karyotyping and c-myc gene analysis.

Main Results:

• The leukemic cells expressed B cell-associated antigens (B4, BA1, HLA-DR) and TdT.
• Surface and cytoplasmic immunoglobulin and cALLA antigen were negative.
• Molecular analysis showed rearranged immunoglobulin heavy chain genes and germ-line T cell β-receptor genes.
• Cytogenetics revealed a normal karyotype with no c-myc gene rearrangement or amplification.
• The findings indicated B-cell precursor ALL of Burkitt type.

Conclusions:

• This case represents a TdT-positive, surface immunoglobulin-negative (Smlg-negative) FAB-L3 ALL.
• The combination of immunological and molecular confirmation in this specific subtype is novel.
• This report contributes to the understanding of rare ALL variants.