Category Archives: WHO Classification

Organ Systems, Bone Marrow, WHO Classification, Hematopathology, Acute Leukemia

EGIL Algorithm for Biphenotypic Blasts

European Group for the Immunological Characterization of Leukemias (EGIL) algorithm for biphenotypic blasts. 
Points
B
T
Myeloid
2
cyCD79a
CD3 (cy or sm)
MPO
 
cyCD22
TCR-αβ
 
 
cyIgM
TCR-γδ
 
1
CD19
CD2
CD117
 
CD20
CD5
CD13
 
CD10
CD8
CD33
 
 
CD10
CDw65
0.5
TdT
TdT
CD14
 
CD24
CD7
CD15
 
 
CD1a
CD64

Biphenotypic leukemia is defined as a score >2 in 2 lineage columns.

WHO 2008/2016 Criteria for Mixed-Phenotype Blasts
Mixed Phenotypic Acute Leukemias (MPAL)
References

Bene MC, Castoldi G, Knapp W, et al. Proposals for the immunological classification of acute leukemias: European Group for the Immunological Characterization of Leukemias (EGIL). Leukemia. 1995;9(10):1783–1786

 

 

Organ Systems, Bone Marrow, WHO Classification, MDS, MDS/MPN

SB3F1 Mutation

  • SB3F1 is a RNA splicesome, mutated SB3F1 may result in an alternative function proteins instead of a loss of function mutation (Obeng, et al.)  
  • Point mutations associated with MDS are in the regions of exons 14 to 16
  • ~25% of all cases of MDS have a SB3F1 mutation
  • ~80% of MDS-RS SLD have SBF3F1 mutation
  • 30-70% of MDS-RS MLD have SB3F1 mutation
  • 20% of MDS/MPN cases have SB3F1 mutation
  • Heterozygous mutation of SB3F1 mutation is associated with disease
  • Obeng et al. demonstrated in mice that an isolated SB3F1 mutation is sufficient to cause MDS-type findings
  • The presence of a SB3F1 mutation has a positive predictive value (PPV) of finding ring sideroblasts of 97.7%.

Continue reading SB3F1 Mutation →

Organ Systems, Bone Marrow, WHO Classification, MDS/MPN, MPN

Chronic Neutrophilic Leukemia (CNL)

Diagnostic Criteria
  • Activating CSF3R mutation (usually T618I or T615A)
  • WBC ≥ 25,000 (at least 80% neutrophils + bands, <10% neutrophil precursors)
    • No dysgranulopoiesis or monocytosis (<1,000/μL)
  • Bone marrow hypercellularity
    • <5% blasts
    • Increased granulopoiesis
    • No evidence of dysgranulopoiesis
  • No molecular abnormalities or diagnostic characteristics of another MPN or MPN/MDS

If a CSF3R mutation is NOT identified, the diagnosis of CNL can still be made if other reactive causes are excluded or other evidence of clonality is identified (persistent for at least 3 months). Continue reading Chronic Neutrophilic Leukemia (CNL) →

PathMD Blog, Bone Marrow, WHO Classification

JAK2, CALR, & MPL Testing in Myeloproliferative Neoplasms (MPN)

Molecular Testing Specimen Adequacy Summary
  • JAK2, CALR, and MPL testing is often performed on peripheral blood specimens in an outpatient setting.
  • JAK2 mutations are preferably analyzed in granulocytes.
  • Peripheral blood and bone marrow specimens are equally adequate for the identification of JAK2 mutations.
  • By extrapolation, CALR and MPL testing on peripheral blood specimens should be equally adequate.

Continue reading JAK2, CALR, & MPL Testing in Myeloproliferative Neoplasms (MPN) →

Organ Systems, Lymph Node, WHO Classification

Extranodal Marginal Zone Lymphoma of Mucosal Associated Lymphoid Tissue (MALT Lymphoma)

Extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT) involves extra nodal tissue and shows infiltration of the marginal zones and inter follicular regions. 
  • Gastric MALT is associated with H. pylori infection in up to 90% of cases. 
  • MALT in the thyroid has been associated with Hashimoto’s thyroiditis (~20% of cases).
  • Ocular MALT lymphomas have been associated with various infections.

Continue reading Extranodal Marginal Zone Lymphoma of Mucosal Associated Lymphoid Tissue (MALT Lymphoma) →