Bone marrow neoplastic
Precursor lymphoid neoplasms
B cell lymphoblastic leukemia / lymphoma

Topic Completed: 1 March 2011

Minor changes: 1 April 2020

Copyright: 2001-2020,, Inc.

PubMed Search: precursor B cell lymphoblastic leukemia OR precursor B cell lymphoblastic lymphoma

Nikhil Sangle, M.D.
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Cite this page: Sangle N. B cell lymphoblastic leukemia / lymphoma. website. Accessed May 31st, 2020.
Definition / general
  • Pre B lymphoblastic leukemia is defined as 20% or more lymphoblasts in bone marrow
  • Disorder of immature B cells that usually affects children, and often presents with diffuse multiorgan involvement
  • Derived from pregerminal center naive B cells with nonmutated Vh region genes
Clinical features
  • Usually children, presents with pancytopenia due to extensive marrow involvement, stormy onset of symptoms, bone pain due to marrow expansion, hepatosplenomegaly due to neoplastic infiltration, testicular involvement, CNS symptoms due to meningeal spread, frequent skin involvement
  • 85% of acute lymphoblastic leukemias (ALL) are B cell, compared to 10 - 20% of lymphoblastic lymphomas (remainder are T cell)
  • Aggressive, but 2/3 cured with chemotherapy
  • Recommended to classify / manage B-ALL with mature phenotype, L1 morphology, and without c-MYC translocations as pre B lymphoblastic / lymphoma, not Burkitt lymphoma (Arch Pathol Lab Med 2003;127:1340)

Lymphoma cases:
  • Median age 20 years, 88% age 35 years or less; 2/3 female, usually extranodal (cutaneous nodules, bone or nodal involvement, NO marrow or mediastinal involvement, Am J Surg Pathol 2000;24:1480)
  • Usually stage 1 or 2
  • Prognosis better than leukemia, but 28% died after median 5 years
  • Often 21q alterations, resembles blastoid variant of mantle cell lymphoma
  • Rarely develop leukemia
Prognostic factors
  • Good prognostic factors: age 2 - 10 years, early pre B phenotype, hyperploidy, t(12,21)
  • Poor prognostic factors (give bone marrow transplantation): under age 2 or teenager / young adult, t(9;22)

B lymphoblastic leukemia / lymphoma with recurrent genetic abnormalities:
  • Good prognosis: t(12;21)(p13;q22) TEL-AML1 (ETV6-RUNX1); blasts with hyperdiploidy (50 - 66 chromosomes with no structural alterations)
  • Poor prognosis: t(9;22)(q34;q11.2) BCR-ABL1; t(v;11q23) MLL rearranged; blasts with hypodiploidy (< 46 chromosomes); t(1;19)(q23;p13.3) E2A-PBX1
Microscopic (histologic) description
  • Intermediate sized blast-like cells with scant cytoplasm, round or convoluted nuclei, fine chromatin, indistinct nucleoli, frequent mitosis
  • May have "starry sky" appearance (similar to Burkitt)
  • Some lymphoblasts have cytoplasmic pseudopods (hand mirror cells); usually no sclerosis
Microscopic (histologic) images

Images hosted on other servers:

TdT negative cases; B cell ALL L1

Positive stains
Negative stains
Molecular / cytogenetics description
  • t(1;14)(q25;q32): IHX4 and IgH
  • t(1;19)(q23;p13): PBX1 and E2A (30%) - unfavorable
  • t(5;14)(q31;q32): IL3 and IgH
  • t(4;11)(q21;q23): AF4 and MLL (10%) - unfavorable
  • t(9;22)(q34;q11): BCR and c-Abl [Philadelphia chromosome] (5 - 20%) - unfavorable
  • t(12,21)(p13;q22): ETV6-CBFA2 (TEL and AML1) (20%) - favorable
  • Most tumors are hyperdiploid (> 50 chromosomes, favorable), some are pseudodiploid
Differential diagnosis
  • AML: prominent nucleoli, delicate chromatin, fine azurophilic cytoplasmic granules, TdT negative, positive for myeloid markers (usually)
  • Also Burkitt lymphoma, granulocytic sarcoma, Hodgkin lymphoma, mantle cell lymphoma blastoid variant
  • Ewing sarcoma: negative for CD43, CD79a, CD179a, CD179b, TdT and immunoglobulin or T cell receptor rearrangement, strong / diffuse for vimentin
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