Lymphoid leukemia

Lymphoid leukemia
Classification and external resources
Specialty oncology
ICD-10 C91
ICD-9-CM 204
MeSH D007945

Lymphoid leukemias — also called lymphocytic, lymphogenous, or lymphoblastic leukemias — are a group of leukemias affecting circulating lymphocytes, a type of white blood cells. The lymphocytic leukemias are closely related to lymphomas of the lymphocytes, to the point that some of them are unitary disease entities that can be called by either name (for example, adult T-cell leukemia/lymphoma). Such diseases are all lymphoproliferative disorders. Most lymphoid leukemias involve a particular subtype of lymphocytes, the B cells.

Classification

Historically, they have been most commonly divided by the stage of maturation at which the clonal (neoplastic) lymphoid population stopped maturing:

However, the influential WHO Classification (published in 2001) emphasized a greater emphasis on cell lineage. To this end, lymphoid leukemias can also be divided by the type of cells affected:

The most common type of lymphoid leukemia is B-cell chronic lymphocytic leukemia.

B-cell leukemias

Lymphoid leukemia
Classification and external resources
Specialty oncology
MeSH D015448

B-cell leukemia describes several different types of lymphoid leukemia which affect B cells.

Comparison of most common B-cell leukemias Incidence Histopathology Cell markers Comments
B-cell chronic lymphocytic leukemia
(ICD-O: 9823/3)		 30% of all leukemias. Also 3 to 4% of lymphomas in adults[1] Small resting lymphocytes mixed with variable number of large activated cells. Lymph nodes are diffusely effaced[1] CD5, surface immunoglobulin[1] Occurs in older adults. Usually involves lymph nodes, bone marrow and spleen. Most patients have peripheral blood involvement. Indolent.[1]
Precursor B-cell lymphoblastic leukemia
(ICD-O: 9835/3-9836/3)		 85% of acute leukemias in childhood,[1] Less common in adults[1] Lymphoblasts with irregular nuclear contours, condensed chromatin, small nucleoli and scant cytoplasm without granules.[1] TdT, CD19[1] Usually presents as acute leukemia[1]

Other types include (with ICD-O code):

T-cell leukemias

T-cell leukemia
Classification and external resources
Specialty oncology
MeSH D015458

T-cell leukemia describes several different types of lymphoid leukemias which affect T cells.

The most common T-cell leukemia is precursor T-cell lymphoblastic leukemia.[1] It causes 15% of acute leukemias in childhood, and also 40% of lymphomas in childhood.[1] It is most common in adolescent males.[1] Its morphology is identical to that of precursor B-cell lymphoblastic leukemia.[1] Cell markers include TdT, CD2, CD7.[1] It often presents as a mediastinal mass because of involvement of the thymus.[1] It is highly associated with NOTCH1 mutations.[1]

Other types include:

In practice, it can be hard to distinguish T-cell leukemia from T-cell lymphoma, and they are often grouped together.

References

  1. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Table 12-8 in: Mitchell, Richard Sheppard; Kumar, Vinay; Abbas, Abul K.; Fausto, Nelson. Robbins Basic Pathology. Philadelphia: Saunders. ISBN 1-4160-2973-7. 8th edition.
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