Lymphoma

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Lymphoma
Classification and external resources
Gastric MALT lymphoma
ICD-10 C81.-C96.
ICD-O: 9590-9999
MeSH D008223
This article is about lymphoma in humans. For the disease in dogs, cats, and ferrets, see lymphoma in animals.

Lymphoma is a type of cancer that originates in lymphocytes of the immune system. They often originate in lymph nodes, presenting as an enlargement of the node (a tumor). Lymphomas are closely related to lymphoid leukemias, which also originate in lymphocytes but typically involve only circulating blood and the bone marrow (where blood cells are generated in a process termed haematopoesis) and do not usually form tumors.[1] There are many types of lymphomas, and in turn, lymphomas are a part of the broad group of diseases called hematological neoplasms.

Thomas Hodgkin published in 1832 the first description of lymphoma, specifically of the form named after him, Hodgkin's lymphoma.[2] Since then many other forms of lymphoma have been described, grouped under several proposed classifications. The 1982 Working formulation classification became very popular. It introduced the category non-Hodgkin lymphoma (NHL), itself divided into 16 different diseases. However, since these different lymphomas have little in common with each other, the NHL label is of limited usefulness for doctors or patients and is slowly being abandoned. The latest classification by the WHO (2001) lists 43 different forms of lymphoma divided in four broad groups.

Some forms of lymphoma are indolent (e.g. small lymphocytic lymphoma), compatible with a long life even without treatment, whereas other forms are aggressive (e.g. Burkitt's lymphoma), causing rapid deterioration and death. The prognosis therefore depends on the correct classification of the disease, established by a pathologist after examination of a biopsy.

Although older classifications referred to histiocytic lymphomas, these are recognized in newer classifications as of B, T or NK cell lineage. True histiocytic malignancies are rare and are classified as sarcomas.[3]

Contents

[edit] Prevalence

According to the U.S. National Institutes of Health, lymphomas account for about five percent of all cases of cancer in the United States, and Hodgkin's lymphoma in particular accounts for less than one percent of all cases of cancer in the United States.

Because the whole system is part of the body's immune system, patients with a weakened immune system, such as from HIV infection or from certain drugs or medication, also have a higher incidence of lymphoma.

[edit] Classification

[edit] Kiel classification

As an alternative to the American Lukes-Butler classification, in the early 1970s, Karl Lennert proposed a new system of classifying lymphomas based on cellular morphology and their relationship to cells of the normal peripheral lymphoid system.

[edit] REAL classification

In the mid 1990s, the Revised European-American Lymphoma (REAL) Classification attempted to apply immunophenotypic and genetic features in identifying distinct clinicopathologic NHL entities. [4]

[edit] WHO classification

The WHO Classification, published in 2001 and updated in 2008[3], is the latest classification of lymphoma and is based upon the foundations laid within the "Revised European-American Lymphoma classification" (REAL). This system attempts to group lymphomas by cell type (i.e.the normal cell type that most resembles the tumor) and defining phenotypic, molecular or cytogenetic characteristics. There are three large groups: the B cell, T cell, and natural killer cell tumors. Other less common groups, are also recognised. Hodgkin's lymphoma, although considered separately within the WHO (and preceeding) classifications, is now recognised as being a tumour of, albeit markedly abnormal, lymphocytes of mature B cell lineage.

[edit] Mature B cell neoplasms

DNA-microarray analysis of Burkitt's lymphoma and diffuse large B-cell lymphoma (DLBCL) showing differences in gene expression patterns. Colors indicate levels of expression; green indicates genes that are underexpressed in lymphoma cells (as compared to normal cells), whereas red indicates genes that are overexpressed in lymphoma cells.

[edit] Mature T cell and natural killer (NK) cell neoplasms

[edit] Hodgkin lymphoma

[edit] Immunodeficiency-associated lymphoproliferative disorders

  • Associated with a primary immune disorder
  • Associated with the Human Immunodeficiency Virus (HIV)
  • Post-transplant
  • Associated with Methotrexate therapy

[edit] Working formulation and Non-Hodgkin lymphoma

The 1982 Working Formulation is a classification of Non-Hodgkin Lymphoma. It has since been replaced by other lymphoma classifications, the latest published by the WHO in 2001 (updated in september 2008), but is still used by cancer agencies for compilation of lymphoma statistics.

[edit] Other classification systems

[edit] Diagnosis, etiology, staging, prognosis, and treatment

See the article of the corresponding form of lymphoma.

[edit] See also

[edit] References

  1. ^ Parham, Peter (2005). The immune system. New York: Garland Science. pp. 414. ISBN 0-8153-4093-1. 
  2. ^ Hellman, Samuel; Mauch, P.M. Ed. (1999). Hodgkin's Disease. Chapter 1: Lippincott Williams & Wilkins. pp. 5. ISBN 0-7817-1502-4. 
  3. ^ a b ed. by Elaine S. Jaffe .... (2001). Pathology and Genetics of Haemo (World Health Organization Classification of Tumours S.). Oxford Univ Pr. ISBN 92-832-2411-6. 
  4. ^ www.emedicine.com on Lymphoma, Non-Hodgkin

[edit] External links

v • d • e
Hematological malignancy/leukemia histology (ICD-O 9590-9989, C81-C96, 200-208)
Lymphoid/Lymphoproliferative, Lymphomas/Lymphoid leukemias (9590-9739, 9800-9839)
By development/
marker
By infection
By development/
marker
By location/peripheral
By infection
NK cell/
(most CD56)
T or NK
Lymphoid+myeloid
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