Precursor B Lymphoblastic Lymphoma
Supplemental Studies
Immunohistology
- TdT positive
- HLA-DR positive
- B lineage positive
- CD19 positive
- CD79a cytoplasmic
- CD22 cytoplasmic
- Surface immunoglobulin does not preclude the diagnosis
- CD10 positive
- Myeloid antigens may infrequently be expressed
- CD13, CD33, CD15
- May be associated with t(9;22) or 11q23 abnormalities, which have unfavorable prognosis
- CD10-/CD15+ phenotype in adults is associated with therapy related leukemia/lymphoma with 11q23 abnormalities, which has unfavorable prognosis
- Scoring system for lineage assignment of leukemias by the European Group for the Immunologic Classification (EGIL)
Score
B-lymphoid
T-lymphoid
Myeloid
2
Cytoplasmic CD79a*
CD3 (membrane/cytoplasmic)
MPO
Cytoplasmic IgM
Anti-TCR
Cytoplasmic CD22
1
CD19
CD2
CD117
CD20
CD5
CD13
CD10
CD8
CD33
CD10
CD65
0.5
TdT
TdT
CD14
CD24
CD7
CD15
CD1a
CD64
- A score of 2.5 is considered sufficient to assign a lineage
- CD79a may also be expressed in a subset of T lymphoblastic leukemia/lymphoma
Genetic analysis
| Abnormality | Gene fusion | Frequency | Prognosis |
|---|---|---|---|
t(9;22)(q34;q11.2) |
BCR/ABL |
3-4% |
Unfavorable |
t(4;11)(q21;q23) |
AF4/MLL |
2-3% |
Unfavorable |
t(1;19)(q23;q13.3) |
PBX/E2A |
6% (25% of pre-B type) |
Unfavorable |
t(12;21)(q13;q22) |
TEL/AML1 |
16-29% |
Favorable |
Hyperdiploid chromosomes 4,10,17 |
|
20-25% |
Favorable |
Hypodiploid |
|
5% |
Unfavorable |
Cytochemistry
- Myeloperoxidase negative
- Sudan Black B negative
