Types of Lymphoma
There are two primary types of lymphoma: Hodgkin lymphoma (HL, also called Hodgkin’s disease), which is characterized by the presence of large distinctive cells called Reed-Sternberg cells, and non-Hodgkin lymphoma (NHL), a large group of about 30 other lymphomas.
Hodgkin lymphoma is most prevalent in two age groups: in those between about 25 and 35 years of age and in those over 55.
Historically, Hodgkin lymphoma was divided into several subtypes (nodular lymphocyte-predominant, nodular sclerosing, mixed cellularity and lymphocyte-depleted). Nowadays the important distinction is between classical HL (cHL), which has some distinctive features, and nodular lymphocyte-predominant HL (nodular LPHD). LPHD behaves quite differently from cHL, and could be thought of as a low-grade non-Hodgkin lymphoma.
Non-Hodgkin lymphoma is the sixth most common cancer in the UK. The incidence of NHL increases with age and is higher in patients with HIV/AIDS and in patients whose immune systems are suppressed. According to Cancer Research UK, in the UK, about 10,000 people are diagnosed with non-Hodgkin lymphoma in one year.
There are about 30 different types of non-Hodgkin lymphoma. Over the years, different classification systems have been used to describe the different types of non-Hodgkin lymphoma as knowledge about the condition has grown. New methods of evaluating the cells involved in non-Hodgkin lymphoma have led to changes in classification systems.
The Revised European American Lymphoma (REAL) looks at the function that the cell should be providing. Some lymphocytes (B-lymphocytes) are responsible for producing antibodies while others (T-lymphocytes) are responsible for cell-to-cell interactions. The newest method, the World Health Organization or WHO Classification, tries to combine all of these characteristics with genetic studies of the cells. Click here to view a table of classifications.
Some Types of Non-Hodgkin Lymphomas
Classification of non-Hodgkin lymphomas can be confusing because there are so many different types and because of the various classification systems that have been developed and amended over the years. B-cell non-Hodgkin lymphomas are much more common than T-cell. About 85% of non-Hodgkin lymphomas involve mature B lymphocytes with about 15% affecting T-lymphocytes.
Some of the more common forms of B-Cell lymphomas include:
- Diffuse large B-cell lymphoma (DLBCL): this form constitutes about 33% of all non-Hodgkin lymphomas. It is a fast growing lymphoma and can affect anyone of any age but occurs mostly in people over 60.
- Follicular lymphomas: these make up about 16% of non-Hodgkin’s lymphoma in the UK. This may be a very slow growing lymphoma.
- B cell chronic lymphocytic leukaemia (CLL) and small lymphocytic lymphoma (SLL): these are identical diseases because they affect the same cell. CLL is found mainly in the bone marrow and the circulating blood while SLL is found mainly in the lymph nodes. These two together make up approximately 24% of all lymphomas.
Some of the more common forms of T-Cell lymphomas include:
- Precursor T-lymphoblastic lymphoma (leukaemia): a disease that can be considered either a lymphoma or leukaemia depending on whether affected cells are found in the blood or whether a certain percentage of bone marrow cells are abnormal. About 1% of all lymphomas are this type.
- Mature or peripheral T-cell lymphomas: there are many different kinds of mature T-cell lymphomas that all together make up about 4% to 5% of all lymphomas.
- Mycosis fungoides (Sézary syndrome), are types of cutaneous T-cell lymphoma: These are less common forms of lymphoma, unusual because, while most lymphomas begin in lymphoid tissue or internal organs, they start in the skin.