Central nervous system (CNS) lymphoma, like other types of lymphoma, is a tumor of white blood cells (lymphocytes) called T cells or B cells. These cells are normally in charge of fighting off bacteria and viruses. CNS lymphoma occurs in the central nervous system, which includes the brain and spinal cord. Brain tumors are much more common than spinal cord tumors.

What Is CNS Lymphoma?

There are two types of CNS lymphoma: primary and secondary. Primary CNS lymphoma starts in the brain or spinal cord itself. In secondary CNS lymphoma, the cancer spreads from lymph nodes in other parts of the body to the brain or spinal cord.

CNS lymphoma is a rare type of lymphoma, and secondary CNS lymphoma is more common than primary CNS lymphoma. Primary CNS lymphoma makes up less than 2 percent of all primary brain tumors (tumors that begin in the brain). However, the incidence (number of new cases) has been rising.

Most primary CNS lymphomas are a type of non-Hodgkin lymphoma called diffuse large B-cell lymphoma. This name refers to the type of immune cell involved in the tumor. A minority of cases are T-cell lymphomas.

Causes of CNS Lymphoma

Doctors don’t know what causes primary CNS lymphoma, but it is associated with a few factors:

• Carrying the Epstein-Barr virus, or the virus that causes mononucleosis (“mono”)
• Having a weakened immune system from an immunodeficiency syndrome such as HIV
• Having an autoimmune disease, such as lupus, that weakens the immune system
• Taking medications that suppress the immune system, such as for an organ transplant
• Being elderly

Symptoms of CNS Lymphoma

People with CNS lymphomas may have nonspecific signs, like headaches or nausea. They may also have mental changes such as memory loss, difficulty concentrating, and behavioral and emotional changes.

In later stages, when the tumor has spread, a person may develop seizures.

CNS lymphoma can eventually travel from the brain to the eye, where it can cause orbital or intraocular lymphoma. Symptoms may include eye inflammation (uveitis), seeing “floaters” (small black or gray spots that move across the eyes), or slowly losing the ability to see as clearly as you used to.

Diagnosis of CNS Lymphoma

Your doctor may use several approaches to determine if you have CNS lymphoma. Whenever there is a brain mass, doctors need to determine whether the mass is lymphoma or some other type of primary brain tumor.

Blood Tests

Because lymphoma is associated with conditions that cause a weakened immune system, your doctor may order blood work to test for conditions such as HIV.

Your doctor may also order a complete blood cell count to see if the lymphoma has entered your bloodstream.

Imaging Tests

To look for secondary CNS lymphoma, your doctor will likely examine the lymph nodes in other parts of the body using scans of the chest and abdomen. These scans may include X-rays, CT scans, MRI scans, and positron emission tomography scans.

Different scans of the brain will also generally be taken to see how far the lymphoma lesions have spread.

Bone Marrow Biopsy

Because the bone marrow creates immune cells, a bone marrow biopsy is usually performed to look for an origin of the lymphoma.

Lumbar Puncture

In some cases, a sample of the fluid surrounding the brain and spinal cord (called cerebrospinal fluid, or CSF) may be taken. This is done through a lumbar puncture (spinal tap).

Flow Cytometry

Special microscopic tests can help your doctor understand what kind of tumor the lymphoma is and what treatments might work best. Flow cytometry, for example, can show which markers are on the surface of the lymphoma cells.

Eye Exam

Lymphomas can spread from the brain to the eyes, so eye doctors may want to take a look into different parts of the eye. Lymphoma cells can invade any part of the eye, including the fluid deep within it (the vitreous humor). Doctors might sample this eye fluid through a procedure called a vitrectomy.

Brain Biopsy

A biopsy of the brain may be required to make a diagnosis if tumor cells are not identified in the cerebrospinal fluid or fluid from the eyes. A neurosurgeon will most likely perform a stereotactic biopsy. This type of biopsy uses imaging scans to find the precise location for the biopsy. A long needle is then used to remove the tissue.

Treatment Options for CNS Lymphoma

The treatment of primary CNS lymphoma involves a combination of chemotherapy and radiation therapy, also known as radiotherapy. You may also undergo stem cell transplantation.

Each of these treatments can have side effects. Your doctor and health care team will be able to work closely with you to find the regimen that works for you. Regular follow-up with your team is also important. Lymphoma can affect many different systems in the body, which may require you to see a different type of doctor or specialist for each.

Chemotherapy

First-line drugs for CNS lymphoma include high-dose chemotherapy, often starting with high-dose methotrexate. For people with orbital lymphoma, some chemotherapy drugs can be injected into the eye to kill lymphoma cells there.

Other common chemotherapy regimens for CNS lymphoma include:

• Rituxan (rituximab)
• Cytarabine
• Oncovin (vincristine)
• Imbruvica (ibrutinib)
• Tepadina (thiotepa)
• Temodar (temozolomide)

CNS lymphoma is often responsive at first to corticosteroid treatment as well.

Radiotherapy

Radiation treatment for CNS lymphoma usually involves whole brain radiation, where the whole brain is subject to radiotherapy. Radiation therapy can also target radiation to specific parts of the brain.

Stem Cell Transplantation

A stem cell transplant can also be considered in addition to chemotherapy and radiotherapy. Stem cell transplantation aims to replace unhealthy immune cells with fresh, healthy cells.

Outlook for CNS Lymphoma

Without treatment, the prognosis (outlook) for someone with CNS lymphoma is a few months. With treatment, many people go on to live years beyond their diagnosis.

Most cases of CNS lymphoma will eventually come back (relapse) within several years. However, with new treatments and clinical trials available, people diagnosed with CNS lymphoma are getting better care and living longer.

Talk With Others Who Understand

MyLymphomaTeam is the social network for people with lymphoma and their loved ones. On MyLymphomaTeam, members come together to ask questions, give advice, and share their stories with others who understand life with lymphoma.

Do you have CNS lymphoma? Share your experience in the comments below, or start a conversation by posting on MyLymphomaTeam.