[CD13- and CD33-negative acute myelocytic leukemia (FAB classification; M2) with morphological changes and CD13
Y Aoyama1, T Yamane, H Kanashima
1Department of Clinical Hematology, Osaka City University Medical School.
Summary
This study reports a rare case of acute myelocytic leukemia (AML) initially lacking CD13/CD33 expression but later showing CD13 expression upon recurrence. This highlights potential shifts in leukemia cell markers over time.
Area of Science:
- Hematology
- Oncology
- Molecular Biology
Background:
- Acute Myelocytic Leukemia (AML) is a heterogeneous hematologic malignancy.
- FAB classification and immunophenotyping (CD markers) are crucial for AML subtyping.
- The t(8;21) chromosomal abnormality is a known genetic hallmark in some AML subtypes.
Observation:
- A 42-year-old male diagnosed with AML (M2) exhibited t(8;21) but lacked CD13 and CD33 expression at initial diagnosis.
- Despite achieving remission via chemotherapy and allogeneic bone marrow transplantation, the patient relapsed approximately 18 months later.
- Morphological analysis at relapse revealed a shift towards AML (M1), with the emergence of CD13 surface antigen expression.
Findings:
- This case presents a rare instance of AML initially negative for both CD13 and CD33.
- A significant finding was the development of CD13 expression at relapse, contrasting with the initial presentation.
- The observed morphological and immunophenotypic changes suggest disease evolution or clonal selection during AML progression.
Implications:
- This case underscores the importance of serial immunophenotyping in monitoring AML, especially in rare presentations.
- Understanding such marker dynamics can refine diagnostic criteria and therapeutic strategies for AML.
- Further research into the mechanisms driving CD marker expression changes in relapsed leukemia is warranted.
