Primary Hematopoietic and Lymphoid Tissue ›› Bone Marrow ›› Lymphoid ›› B-cells ›› Abnormal
Increased B-Lymphoblasts
›Microscopic Features:
- 3-4x larger than a mature RBC
- High nuclear to cytoplasmic ratio
- Round Nucleus with immature chromatin (not clumped)
- Prominent nucleoli
- Cytoplasm is scant, light blue and lacks granules
›Normal % blood-PB, marrow-BM, lymphoid tissue-LN:
- PB: None
- BM: None
- LN: None
›May Resemble:
›Differential Diagnoses:
If in blood or increased numbers in bone marrow:
B-Lymphoblastic leukemia/lymphoma (B-ALL)
CML lymphoblastic Bast crisis (usually it's myeloblasts but can sometimes be lymphoblasts)
B-Lymphoblastic leukemia/lymphoma (B-ALL)
CML lymphoblastic Bast crisis (usually it's myeloblasts but can sometimes be lymphoblasts)
›Classic Immunophenotype:
- CD19+
- CD10+
- CD20-
- CD34+
- TdT+
›Cartoon Image:
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›Misc:
Blasts cells cannot be reliably distinguished from each other based on morphology alone. The exception are blasts with Auer Rod(s) which are unique to abnormal Myeloblast {16}s and abnormal promyelocytes as noted in some AMLs and APL
Note: Abnormal B-lymphoblasts can show immunophenotypic abberancies (e.g. the gain of myeloid markers)
Note: Abnormal B-lymphoblasts can show immunophenotypic abberancies (e.g. the gain of myeloid markers)