There are two types of central nervous system (CNS) lymphoma:
- Primary CNS lymphoma begins in the nervous system and is confined to the brain, spine, cerebrospinal fluid (the liquid around the brain and spinal cord), and eyes.
- Secondary CNS lymphoma begins in another part of the body and later spreads to the nervous system.
Primary CNS Lymphoma
Lymphoma is categorized by the white blood cells it affects. Most cases of primary CNS lymphoma, about 90 percent, are a type of lymphoma called diffuse large B-cell lymphoma. The other 10 percent of cases are made up of other kinds of lymphoma. These include Burkitt lymphoma, T cell lymphoma, and low-grade lymphomas.
Genetic studies of diffuse large B-cell lymphoma have identified that there are three main subtypes. Most of the diffuse large B-cell lymphomas that spread to the nervous system are a subtype called ABC/NGC.
Advanced genomic sequencing has identified certain mutations that are common in primary CNS lymphoma. These genetic changes suggest new targets for personalized medicine.
The risk factors for primary CNS lymphoma are unknown.
Secondary CNS Lymphoma
Certain types of non-Hodgkin lymphoma are more aggressive than others. Lymphoma that is more aggressive is more likely to spread to the nervous sytem from other parts of the body. These types include Burkitt lymphoma and diffuse large B-cell lymphoma. Other less-aggressive lymphomas, such as follicular lymphoma, are less likely to spread.
Risk factors for developing secondary CNS lymphoma include:
- advanced (stage III or IV) disease in other parts of the body
- lymphoma in the testes, sinuses, breasts, lymph nodes in the pelvis, or bone marrow
- lymphoma in more than one part of the body outside the lymph nodes
- elevated blood levels of low-density lipoprotein (LDL, or “bad,” cholesterol)
- low levels of a protein called albumin in the blood
- being older than 60 years
People who are at an increased risk of developing secondary CNS lymphoma may receive preventive chemotherapy with a drug called methotrexate (Rheumatrex®, Trexall®). The drug is put directly into the spine.