exam 3 Flashcards
Precursor B lymphoblastic leukemia/ lymphoma
a neoplasm of lymphoblast’s committed to the B - cell lineage
B-LBL vs B-ALL
B-LBL: lymphoma mass, with or without minimal blood and BM involvement
Precursor B lymphoblastic leukemia epidemiology
B-LBL: 10% of lymphoblastic lymphoma, 75% of cases in patients under 18 years old
B-ALL: 75% of cases in children under 6 years old
Clinical features of B-ALL and B-LBL
B-ALL: WBC decreased, normal or markedly elevated, Anemia, thrombocytopenia, lymphadenopathy, hepatosplenomegaly, bone pain, arthralgias
B-LBL: skin, bone, soft tissue, and lymph node
Sites of involvement and morphology in Precursor B LL
B-ALL: blood and bone marrow in all cases
B-LBL: skin, bone, soft tissue, and lymph node, rare in mediastinal mass
Immunophenotype in Precursor BLL
TdT, HLA-DR
CD19, CD79a, CD10, CD24
t(4;11)(q21;q23) cases are typically negative for CD10 and CD24
Variably positive for CD20 and CD22
CD45 may be negative
Cytoplasmic Mu chain in pre-B ALL
Precursor BLL genetics
t(9;22)(q34;q11.2): 3-4% of cases, in most childhood cases associated with 190 kd, BCR/ABL fusion tyrosine kinase, unfavorable prognosis
t(4;11)(q21;q23): associated with AF4/MLL, 2-3% of cases, unfavorable prognosis
t(1;19)(q23;p11.3): associated with PBX/E2A. 6% of cases( 25% of pre - B ALL), unfavorable prognosis
t(12;21)(p13;q22): associated with TEL/AML-1, 16-29% of cases, favorable prognosis
Hyperdiploidy vs. Hypodiploidy
Hyperdiploidy: 20-25% of cases, favorable prognosis (>50)
Hypoploidy: 5% of cases, unfavorable prognosis (<50)
B - LL Differential diagnosis
Precursor T-ALL and AML: resolved with immunophenotyping
Hematogones ( normal B precursors): mimic blasts morphology, positive for TdT, CD34, CD10, pan B markers, in very young patients or in older patients with neuroblastoma, post - chemo, iron deficiency, ITP
Burkitt lymphoma
Blastoid variant of mantle cell lymphoma (positive for bcl-1, negative for TdT
Prognosis of B-LL
B-ALL: good prognosis in the pediatric group, 80% of patients cured, poorer diagnosis in adult group with more unfavorable genetic results
B-LBL: median survival of 60 months
Precursor T lymphoblastic leukemia/lymphoma
A neoplasm of lymphoblast committed to the T-cell lineage
lymphoma vs. lymphoblastic leukemia
Lymphoma: mass, without or minimal blood and BM involvement
Lymphoblastic leukemia: extensive BM and blood involvement (>25% BM cells)
Precursor T-LL epidemiology
15% of childhood ALL
25% of adult ALL
80-95% of lymphoblastic lymphoma
More in adolescents and males
Clinical features of T-LL
Leukemia: high WBC
Lymphoma: large mediastinal mass ( or other tissue mass), rapid growth, pleural fluid involvement
T-LL sites of involvement
Leukemia: blood and BM, all cases
Lymphoma: mediastinal mass: 50%, others include LN< skin, liver, spleen, Waldeyers ring, CNS, gonads
Morphology of T-LL
Similar to B-ALL/ LBL
High number of mitotic figures
A small number of LBL cases wiht eosinophilia, myeloid hyperplasia, some associated with t(8;13)(p11.2;q11-22), some of them developed myeloid malignancy
Cytochemistry of T-LL
acid phosphatase, TdT, PAS: nuclear
T-LL immunophenotype
TdT positive, cCD3 (the only lineage specific marker), CD4,8: double negative or positive, Variable surface: CD1a,2,3,4,7,10,79a,13,33,117( rare), TCR: may have rearrangement, not lineage specific