White-cell neoplasms: classification
- Topic
Blood cancers are sorted by the cell they come from and where they live. Markers, genes and the normal cell they copy decide the name.
What it is
White-cell neoplasms are classified (WHO and International Consensus systems) by lineage, maturity and genetics, not just by whether they sit in the blood or in a mass. Leukaemia means wide marrow and blood involvement; lymphoma means a mass in nodes or tissues, but many entities can present either way. Lymphoid neoplasms are B, T or NK; myeloid neoplasms include acute myeloid leukaemia, myelodysplastic and myeloproliferative neoplasms. Most lymphomas copy a stage of normal B-cell development, which explains their markers and genetics.
Step by step
- Look at the cells: size, nuclear chromatin, nucleoli, granules and Auer rods.
- Look at the architecture in node or marrow biopsy: follicular, diffuse, sinusoidal or paratrabecular patterns.
- Immunophenotype by flow cytometry and immunohistochemistry: lineage and maturation stage.
- Genetics: karyotype, FISH and sequencing for defining translocations and mutations.
- Combine with the clinical picture: age, sites, tempo of disease.
The four classic leukaemias compared
| Leukaemia | Typical age | Cell on the smear | Key markers or genetics | Classic clue |
|---|---|---|---|---|
| Acute lymphoblastic leukaemia (ALL) | Children (peak early childhood) | Lymphoblasts, scant cytoplasm, fine chromatin | TdT, CD10, CD19 (B-ALL); CD3 (T-ALL) | Bone pain, mediastinal mass in T-ALL, CNS and testis relapse |
| Acute myeloid leukaemia (AML) | Adults, rising with age | Myeloblasts with nucleoli and granules | Myeloperoxidase, CD33, CD117, CD34 | Auer rods; DIC in promyelocytic type |
| Chronic lymphocytic leukaemia (CLL) | Older adults | Small round mature lymphocytes, smudge cells | CD5 and CD23 on B cells | Hypogammaglobulinaemia, autoimmune haemolysis |
| Chronic myeloid leukaemia (CML) | Middle age | Granulocytes at all stages, basophils | BCR::ABL1, t(9;22) | Huge spleen, blast crisis if untreated |
Markers
- TdT
- CD19
- CD20
- CD3
- CD34
- CD33
- CD117
- MPO
- CD15
- CD30
- CD138
Clinical notes
- Neoplasms of immune cells often cause immune disorders too: infections from lost immunity and autoimmune cytopenias from broken tolerance.
- Myeloid neoplasms almost always involve the marrow; lymphomas often start in nodes and spread to marrow later.
Test yourself
Think of the answer, then tap the question to see it.
Which marker distinguishes lymphoblasts from mature lymphocytes?
Terminal deoxynucleotidyl transferase (TdT), expressed only in pre-B and pre-T lymphoblasts.
How does light-chain restriction prove a B-cell population is clonal?
A reactive population mixes κ and λ cells; a clone expresses only one of them.
What proportion of lymphoid neoplasms are B-cell tumours?
About 85 to 90 percent.
Elsewhere in DurgiPedia
- Hematopoiesis and bone marrow
- B-cell activation, class switching and affinity maturation
- Hematopoiesis
- Bone marrow and hematopoiesis of immune cells
Connections
Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.
Sources: Non-Hodgkin Lymphoma Treatment (PDQ®)–Patient Version (National Cancer Institute (NCI), 2026); Acute Myeloid Leukemia Treatment (PDQ®)–Patient Version (National Cancer Institute (NCI), 2026).
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Representative model, for educational purposes only.