Lymphoma is a form of cancer that affects the immune system - specifically, it is a cancer of immune cells called lymphocytes, a type of white blood cell. There are two broad types of lymphoma and many subtypes.
For most cancers, researchers are still trying to understand how they are caused. The same is true for lymphoma - doctors do not know what causes it, although it is more likely to occur in certain people.
Medical researchers have identified certain risk factors that make lymphoma more likely, although they often do not understand why.
What Are the Types of Lymphoma?
Lymphomas fall into one of two major categories: Hodgkin's lymphoma (HL, previously called Hodgkin's disease) and all other lymphomas (non-Hodgkin's lymphomas or NHLs).
- These two types occur in the same places, may be associated with the same symptoms, and often have similar appearance on physical examination (for example, swollen lymph nodes). However, they are readily distinguishable via microscopic examination of a tissue biopsy sample because of their distinct appearance under the microscope and their cell surface markers.
- Hodgkin's disease develops from a specific abnormal B lymphocyte lineage. NHL may derive from either abnormal B or T cells and are distinguished by unique genetic markers.
- There are five subtypes of Hodgkin's disease and about 30 subtypes of non-Hodgkin's lymphoma (not all experts agree on the numbers and names of these NHL subtypes).
- Because there are so many different subtypes of lymphoma, the classification of lymphomas is complicated (it includes both the microscopic appearance as well as genetic and molecular markers).
- Many of the NHL subtypes look similar, but they are functionally quite different and respond to different therapies with different probabilities of cure. For example, the subtype plasmablastic lymphoma is an aggressive cancer that arises in the oral cavity of HIV-infected patients, the follicular subtype is composed of abnormal B lymphocytes, while anaplastic subtype is comprised of abnormal T cells and cutaneous lymphomas localize abnormal T cells in the skin. As previously mentioned, there are over 30 subtypes of NHL with unusual names such as Mantle cell lymphoma, mucosa associated lymphoid tissue (MALT) lymphoma, hepatosplenic lymphoma and hereditary lymphomas. However, the World Health Organization (WHO) suggests there at least 61 types of NHL; subtyping is still a work in progress. However, no matter how many subtypes experts suggest exist, there are too many to discuss in detail in this article. HL subtypes are microscopically distinct, and typing is based upon the microscopic differences as well as extent of disease.
- Lymphoma is the most common type of blood cancer in the United States. It is the seventh most common cancer in adults and the third most common in children. Non-Hodgkin's lymphoma is far more common than Hodgkin's lymphoma.
In the United States, about 72,580 new cases of NHL and 8,500 new cases of HL were expected to be diagnosed in 2016, and the overall incidence is increasing each year.
About 20,150 deaths due to NHL were expected in 2016as well as 1,120 deaths due to HL, with the survival rate of all but the most advanced cases of HL greater than that of other lymphomas.
Lymphoma can occur at any age, including childhood. Hodgkin's disease is most common in two age groups: young adults 16-34 years of age and in older people 55 years of age and older. Non-Hodgkin's lymphoma is more likely to occur in older people. Continue Reading
What facts of lymphoma?
Here are some key points about lymphoma :
- Lymphoma is cancer that develops in the lymph nodes and lymphatic system.
- The two main types of lymphoma are non-Hodgkin's (about 90% of cases) and Hodgkin's (about 10%).
- The main symptom is usually enlargement of lymph nodes that does not go away (as it does after infection).
- There are an estimated 761,659 people living with, or in remission from, lymphoma in the US.3
- For Hodgkin's lymphoma, an estimated 177,526 people are living with the disease or are in remission.
- For non-Hodgkin's lymphoma, an estimated 584,133 people are living with the disease or are in remission.
- There are around 79,990 new cases of lymphoma diagnosed in the US each year (9,190 cases of Hodgkin's lymphoma, 70,800 cases of non-Hodgkin's lymphoma).
- Lymphoma cannot be prevented, but survival rates after treatment are good.