Contributions
Abstract: PB1651
Type: Publication Only
Background
The finding of cytoplasmic granules in blasts is one of main morpholoic features to distinguish AML from ALL. Rarely, significant and thick granules may be presented in cytoplasm of blasts in ALL, known as granular acute lymphoblastic leukemia, indicating a worse prognosis. IKZF1 deletion is an independent prognostic marker in childhood B-cell precursor acute lymphoblastic leukemia.
Aims
Morphology and cytochemical evaluation of peripheral blood or bone marrow aspirate smears are still main examinations to diagnose hematological diseases. To reduce the misdiagnosis and improve the prognosis of granular ALL , it is neccsary to understand its features differed to AML and classic ALL.
Methods
Morphology, flow cytometry, leukemia related fusion genes screen and karyotype analysis were applied in this 12-year-old boy whose white blood cell of peripheral blood rise obviously. csary to understand its features differed to AML and classic ALL.
Results
The peripheral blood and bone marrow blasts showed abundant of cytoplasmic granules(panel a and b; original magnification *1000, Wright-Giemsa stained) and were positive for CD10, CD19, CD20, CD34, HLA-DR, cCD79a, terminal deoxynucleotidyltransferase and CD22(partial). The heavily granulated lymphoblasts in the blastic population of bone marrow aspirate was 53.0%. These blasts were positive for Periodic Acid-Schiff reaction(panel c) but completely negative for myeloperoxidase(panel d) by cytochemical staining. His FAB subtype of morphology was L2. More than 30 leukemia fusion genes were screened and the results were negative. A heterozygous deletion of Exon 4-8 in IKZF1 gene was found. Cytogenetic analysis brought normal karyotype 46 XY. His prognosis was poor with VDLP chemotherapy (vincristine sulfate, daunorubicin, pamnidase, prednisone acetate, dexamethasone) induced chemotherapy was given successively.
Conclusion
Granular ALL is a rare morphologic subtype of ALL which was reported in just over 100 cases. Those large cytoplasmic granules closely mimicked heavily granulated myeloblasts in acute myeloid leukemia. The granules of granular ALL are thought to be the result of dysplastic organella formation, fusion, or degeneration, such as multivesicular bodies or Gall Bodies. Granular ALL may not only cause problematic distinction from myeloid differntiation but also associated with a worse prognosis when compared to other ALL patients. This patient was in a high risk of bad prognosis for granular ALL subtype and heterozygous deletion of IKZF1. We should keep in mind since this ALL subtype may easily be mistaken for acute myeloid leukemia during morphologic evaluation. This potentiality further emphasizes the importance of molecular diagnosis and immunophenotype in the characterization of leukemias.
Session topic: 2. Acute lymphoblastic leukemia - Clinical
Abstract: PB1651
Type: Publication Only
Background
The finding of cytoplasmic granules in blasts is one of main morpholoic features to distinguish AML from ALL. Rarely, significant and thick granules may be presented in cytoplasm of blasts in ALL, known as granular acute lymphoblastic leukemia, indicating a worse prognosis. IKZF1 deletion is an independent prognostic marker in childhood B-cell precursor acute lymphoblastic leukemia.
Aims
Morphology and cytochemical evaluation of peripheral blood or bone marrow aspirate smears are still main examinations to diagnose hematological diseases. To reduce the misdiagnosis and improve the prognosis of granular ALL , it is neccsary to understand its features differed to AML and classic ALL.
Methods
Morphology, flow cytometry, leukemia related fusion genes screen and karyotype analysis were applied in this 12-year-old boy whose white blood cell of peripheral blood rise obviously. csary to understand its features differed to AML and classic ALL.
Results
The peripheral blood and bone marrow blasts showed abundant of cytoplasmic granules(panel a and b; original magnification *1000, Wright-Giemsa stained) and were positive for CD10, CD19, CD20, CD34, HLA-DR, cCD79a, terminal deoxynucleotidyltransferase and CD22(partial). The heavily granulated lymphoblasts in the blastic population of bone marrow aspirate was 53.0%. These blasts were positive for Periodic Acid-Schiff reaction(panel c) but completely negative for myeloperoxidase(panel d) by cytochemical staining. His FAB subtype of morphology was L2. More than 30 leukemia fusion genes were screened and the results were negative. A heterozygous deletion of Exon 4-8 in IKZF1 gene was found. Cytogenetic analysis brought normal karyotype 46 XY. His prognosis was poor with VDLP chemotherapy (vincristine sulfate, daunorubicin, pamnidase, prednisone acetate, dexamethasone) induced chemotherapy was given successively.
Conclusion
Granular ALL is a rare morphologic subtype of ALL which was reported in just over 100 cases. Those large cytoplasmic granules closely mimicked heavily granulated myeloblasts in acute myeloid leukemia. The granules of granular ALL are thought to be the result of dysplastic organella formation, fusion, or degeneration, such as multivesicular bodies or Gall Bodies. Granular ALL may not only cause problematic distinction from myeloid differntiation but also associated with a worse prognosis when compared to other ALL patients. This patient was in a high risk of bad prognosis for granular ALL subtype and heterozygous deletion of IKZF1. We should keep in mind since this ALL subtype may easily be mistaken for acute myeloid leukemia during morphologic evaluation. This potentiality further emphasizes the importance of molecular diagnosis and immunophenotype in the characterization of leukemias.
Session topic: 2. Acute lymphoblastic leukemia - Clinical