|
|
|
Lymphoma is a cancer in the lymphatic cells of the immune system. Typically, lymphomas present as a solid tumor of lymphoid cells. Treatment might involve chemotherapy and in some cases radiotherapy and/or bone marrow transplantation, and can be curable depending on the histology, type, and stage of the disease. These malignant cells often originate in lymph nodes, presenting as an enlargement of the node (a tumor). It can also affect other organs in which case it is referred to as extranodal lymphoma. Extranodal sites include the skin, brain, bowels and bone. 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 static tumors. 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 the first description of lymphoma in 1832, specifically of the form named after him, Hodgkin's lymphoma. 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), divided into 16 different diseases. However, because 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.
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.
|
|
|
| Other classification systems : Immunodeficiency-associated lymphoproliferative disorders |
|---|
| Precursor T-cell leukemia/lymphoma |
|---|
| Follicular lymphoma |
40% of lymphomas in adults |
Small "cleaved" cells (centrocytes) mixed with large activated cells (centroblasts). Usually nodular ("follicular") growth pattern |
CD10, surface Ig |
72-77% |
Occurs in older adults. Usually involves lymph nodes, bone marrow and spleen.[ Associated with t(14;18) translocation overexpressing Bcl-2.][ Indolent] |
| Diffuse large B cell lymphoma |
40 to 50% of lymphomas in adults |
Variable. Most resemble B cells of large germinal centers. Diffuse growth pattern. |
Variable expression of CD10 and surface Ig |
60% |
Occurs in all ages, but most commonly in older adults. Often occurs outside lymph nodes. Aggressive. |
| Mantle cell lymphoma |
3 to 4% of lymphomas in adults |
Lymphocytes of small to intermediate size growing in diffuse pattern |
CD5 |
50%[ to 70%] |
Occurs mainly in adult males. Usually involves lymph nodes, bone marrow, spleen and GI tract. Associated with t(11;14) translocation overexpressing cyclin D1. Moderately aggressive. |
| B-cell chronic lymphocytic leukemia/lymphoma |
3 to 4 % of lymphomas in adults |
Small resting lymphocytes mixed with variable number of large activated cells. Lymph nodes are diffusely effaced |
CD5, surface immunoglobulin |
50%. |
Occurs in older adults. Usually involves lymph nodes, bone marrow and spleen. Most patients have peripheral blood involvement. Indolent. |
| MALT lymphoma |
~5% of lymphomas in adults |
Variable cell size and differentiation. 40% show plasma cell differentiation. Homing of B cells to epithelium creates lymphoepithelial lesions. |
CD5, CD10, surface Ig |
|
Frequently occurs outside lymph nodes. Very indolent. May be cured by local excision. |
| Burkitt's lymphoma |
< 1% of lymphomas in the United States |
Round lymphoid cells of intermediate size with several nucleoli. Starry-sky appearance by diffuse spread with interspersed apoptosis. |
CD10, surface Ig |
50% |
Endemic in Africa, sporadic elsewhere. More common in immunocompromised and in children. Often visceral involvement. Highly aggressive. |
| Mycosis fungoides |
Most common cutaneous lymphoid malignancy |
Usually small lymphoid cells with convoluted nuclei that often infiltrate the epidermis, creating Pautier microabscesses |
CD4 |
75% |
Localized or more generalized skin symptoms. Generally indolent. In a more aggressive variant, [Sézary's disease, there is skin erythema and peripheral blood involvement.] |
| Peripheral T-cell lymphoma-Not-Otherwise-Specified |
Most common T cell lymphoma |
Variable. Usually a mix small to large lymphoid cells with irregular nuclear contours. |
CD3 |
|
Probably consists of several rare tumor types. It is often disseminated and generally aggressive. |
| Nodular sclerosis form of Hodgkin lymphoma |
Most common type of Hodgkin's lymphoma |
Reed-Sternberg cell variants and inflammation. usually broad sclerotic bands that consists of collagen. |
CD15, CD30 |
|
Most common in young adults. It often arises in the mediastinum or cervical lymph nodes. |
| Mixed-cellularity subtype of Hodgkin lymphoma |
Second most common form of Hodgkin's lymphoma |
Many classic Reed-Sternberg cells and inflammation |
CD15, CD30 |
|
Most common in men. More likely to be diagnosed at advanced stages than the nodular sclerosis form. Epstein-Barr virus involved in 70% of cases. |
RSS
