Pre-B Acute Lymphoblastic Leukemia During a Complete Remission in T-Acute Lymphoblastic Leukemia

Area of Science:

• Hematology
• Oncology
• Immunology

Background:

• Acute lymphoblastic leukemia (ALL) is a heterogeneous hematologic malignancy.
• Subtypes of ALL, such as T-ALL and B-ALL, are defined by distinct immunophenotypic and morphologic characteristics.
• Phenotypic plasticity in leukemia can complicate diagnosis and treatment.

Purpose of the Study:

• To report a unique case of a phenotypic switch in acute lymphoblastic leukemia.
• To investigate the immunophenotypic and morphologic changes during leukemic relapse.

Main Methods:

• Morphological analysis using the French, American, and British (FAB) classification.
• Immunophenotyping of blast cells using flow cytometry.
• Assessment of acid phosphatase staining.

Main Results:

• Initial diagnosis: T-ALL (L2 morphology, CD2+, CD5+, CD7+, CD10-, acid phosphatase positive).
• Relapse: Phenotypic switch to pre-B ALL (L1 morphology, CD10+, CD5+, CD2-, CD5-, CD7-).
• Complete remission achieved initially, followed by relapse with altered leukemia characteristics.

Conclusions:

• The findings suggest a potential clonal evolution or transformation from T-ALL to pre-B ALL.
• The possibility of a secondary leukemia developing in the same patient cannot be entirely excluded.
• This case underscores the importance of re-evaluating immunophenotype at relapse.