Types of Non-Hodgkin's Lymphoma & Classification Systems

Over the years, several classification systems have been used to differentiate among the various types of non-Hodgkin's lymphoma including:

• Rappaport: Used until the 1970s, Rappaport was based on morphology (how the cells look under a microscope) alone.
• Kiel: Used mainly in Europe, the Kiel system is based on morphologic and immunologic (what types of proteins are produced by the cell) criteria; updated in 1992.
• National Cancer Institute's Working Formulation (IWF): The IWF divided lymphomas into low-grade, intermediate-grade and high-grade, with ten sub-groups labeled A to J.
• Revised European-American Classification of Lymphoid Neoplasms (REAL): Introduced in 1994, REAL describes the different types of lymphomas as entities, with each type classified according to cell origin, based on morphologic, immunologic and genetic criteria.
• World Health Organization (WHO): The most recent classification system is an updated version of REAL and was introduced in 2001 as an international standard. The WHO system uses the latest information on the appearance and growth pattern of the cancerous cells and genetic features. It also offers a more accurate description of the different types of tumors and identifies several new categories of non-Hodgkin's lymphatic cancer.

New Developments

In recent years, many advances have been made in the development of diagnostic procedures. As a result of the discovery of a number of new types and sub-types of NHL, physicians can tailor treatment to a particular category of disease with increasing accuracy.

NHL Classification Summary*

*based on WHO (2001)

Examples of NHL Types

Unlike Hodgkin's disease, NHL has many sub-types. Depending on the diagnosis, the patient will be placed in a particular prognostic group and receive individualized treatment specific to that cancer category. Each category is further classified according to how aggressively the cancer spreads:

• diffuse large B-cell lymphoma (DLBCL): This B-cell lymphoma is the most common type of NHL. It occurs in children as well as adults and accounts for thirty to forty percent of all cases of NHL.
• small lymphocytic: This type of NHL involves mature-looking B-cells and occurs most frequently in older people. The disease spreads throughout several lymph nodes and often involves the spleen, liver and bone marrow. The small lymphocytic lymphoma type includes lymphoplasmacytic lymphoma, B-cell chronic lymphocytic leukemia and B-cell prolymphocytic leukemia. The disease is closely related to chronic lymphocytic leukemia.
• follicular (follicle center lymphoma): This is a common B-cell type, where the affected cells resemble those found in follicles (nodules) of lymph nodes. Follicular cells often undergo translocation between chromosomes 14 and 18. Translocation occurs when one chromosome becomes abnormally attached to part of a different chromosome.
• mantle cell (MCL): This is a B-cell lymphoma derived from cells found in the ""mantle"" or outer rim of secondary follicles. One of the features of this type is a translocation that occurs between chromosomes 11 and 14.
• mucosa-associated lymphoid tissue (MALT): MALT originates in the lymphatic tissue that lines the gastrointestinal tract. This lymphatic cancer tends to occur in the salivary glands, thyroid glands, lungs and stomach and is often preceded by chronic inflammation of the immune system.
• precursor T-lymphoblastic: Common in children, this type often progresses to acute lymphoblastic leukemia.
• Burkitt: This is an aggressive B-cell lymphoma associated with Epstein-Barr virus (EBV) infection and a characteristic chromosomal alteration, with a translocation between chromosomes 8 and 14.
• cutaneous T-cell lymphomas: These are rare lymphatic cancers and include subcutaneous panniculitis-like T-cell lymphoma, Mycosis fungoides and Sézary syndrome, which present with skin lesions.

Childhood Non-Hodgkin's Lymphomas

Almost all childhood NHLs belong to one of three main categories of the disease. All three are high grade and diffuse. Distinguishing among the three categories is important, though, because their treatments differ considerably.

• Lymphoblastic lymphoma (LBL): LBL accounts for about thirty percent of childhood lymphatic cancers (compared with five percent in adults). LBL derives from T-cells in the thymus and develops in the chest region known as the anterior mediastinum. Occasionally it occurs in the neck or tonsils. LBL is most common in teenagers, with boys affected twice as often as girls. Typically, it spreads rapidly to other lymph nodes, bone marrow, the brain surface, the lungs and the heart.
• Small noncleaved cell lymphoma (SNCL): SNCL accounts for around forty percent of childhood NHLs in the US and almost all cases of NHL in certain regions of Africa. Worldwide, this type accounts for almost fifty percent of all childhood cancers. The two main sub-types of SNCL are Burkitt's and non-Burkitt's lymphoma. Treatment for both types is the same. SNCL tends to develop in the facial bones, especially the jaws of African children, but in affected children elsewhere in the world it is more commonly found in the abdomen. SNCL derives from B-lymphocytes and is particularly fast growing. It tends to spread rapidly to other organs such as the brain or brain surface.
• Large cell lymphoma (LCL): LCL accounts for thirty percent of NHLs in children. Its main subtypes are large cell, immunoblastic and anaplastic large cell lymphoma (ALCL). The first two usually develop from B-cells, whereas ALCL typically develops from T-cells. LCL tends to develop in the neck, chest (mediastinum, thymus), throat, or abdomen and often spreads quickly to the skin. This type rarely spreads to the bone marrow or brain.

Resources

American Cancer Society. (updated 2005). What is childhood non-Hodgkin's lymphoma?

Beers, M. H.,