What is follicular lymphoma?

Follicular lymphoma is a cancer of B cells. B cells are white blood cells that make antibodies to fight infection. They live in your lymph nodes, spleen, bone marrow, and blood. It is the most common slow-growing (indolent) lymphoma. It gets its name because the cancer cells gather in round clusters, called follicles, inside the lymph node. It is most common in people in their 60s.

When should I call my care team?

Fever of 100.4 F (38 C) or higher, or chills; Confusion, trouble speaking, shaking, or being very hard to wake up, especially after CAR T-cell therapy or a bispecific antibody; Trouble breathing, chest pain, or a fast heartbeat; Chills, wheezing, or swelling of the lips or throat during or after an antibody infusion; Swelling of the face, neck, or arms, or new trouble swallowing; A lump that grows quickly over days to weeks, or new belly pain or swelling; Bleeding that will not stop, or new bruises or tiny red spots on the skin; Swelling, pain, or warmth in one leg, which can be a blood clot; Vomiting or diarrhea that will not stop, or you cannot keep fluids down; Yellow skin or eyes.

Follicular lymphoma

Follicular lymphoma is a slow-growing blood cancer. Many people do not need treatment right away, and most live well with it for many years.

Hi, I'm Rosa. Today we'll go through follicular lymphoma together, one step at a time. I'll keep it simple, and you can pause me, go back, or skip ahead whenever you like. Just so you know, this is for learning only. It is not medical advice, so please check everything with your own doctor and care team. Okay, let's get started.

What follicular lymphoma is

Let's start with the basics. Follicular lymphoma is a cancer of B cells. B cells are white blood cells that fight infection. In this lymphoma, B cells grow in round clusters inside the lymph nodes. It is the most common slow-growing lymphoma. Many people have no symptoms at all. Some notice a painless lump that comes and goes. For most people, it cannot be cured yet. But it often grows very slowly, and it usually responds well to treatment. Many people live well with it for many years.

Types and grades

Now let's talk about types. Most people have the classic type. Doctors give it a grade. The grade tells how many large cells they see. Grades 1, 2, and 3A act slowly and are treated the same way. Grade 3B acts faster and is treated like a fast-growing lymphoma. Sometimes follicular lymphoma changes into a fast-growing type. This is called transformation. A lump that grows quickly can be a sign. If that happens, you will need a new biopsy and stronger treatment.

Tests you may have

Next, let's go over tests. A biopsy is the key test. A doctor removes a lymph node, or part of one. It shows the type and the grade. A PET-CT scan shows where the lymphoma is. It can also point to an area that may be growing faster. Blood tests check your counts, liver, and kidneys. You will also be tested for hepatitis before antibody medicines. Some people need a bone marrow biopsy. You can read more about each test in the guide.

Stage and when to treat

Next up, the stage. The stage tells how far the lymphoma has spread. Most people have stage 3 or 4 when it is found. That is very common, and it does not mean things are hopeless. With this lymphoma, the big question is when to treat. Your doctor looks at how much lymphoma there is. They check if it is causing problems. For example, a very big lump, fevers, sweats, or low blood counts. If there are no problems, many people can safely wait. If there are problems, treatment usually starts.

Lab and gene tests

Before we move to treatment, a word on lab tests. The lab checks your biopsy for markers on the cells. One marker, called CD20, is on almost all follicular lymphoma cells. Antibody medicines attach to it. Most of these lymphomas also have a gene swap that helps the cells live too long. Some have a gene change called EZH2. A pill can target it if the lymphoma comes back. You do not need to memorize any of this. Your doctor will explain your results. The Questions to ask page can help too.

Main treatment options

Now let's look at treatment. If the lymphoma is not causing problems, watch and wait is often best. It is a proven plan, not doing nothing. If it is in just one area, radiation may cure it. When treatment is needed, many people get chemotherapy plus an antibody medicine. A common plan is bendamustine with rituximab. Another plan uses a pill called lenalidomide with rituximab. Some people get the antibody every few months afterward to keep the lymphoma away longer. If the lymphoma comes back, there are many good options. These include medicines that bring your immune cells to the lymphoma. Another option changes your own immune cells in a lab to fight it. Clinical trials may offer new options too.

Side effects and what helps

Let's talk about side effects. Antibody medicines can cause chills or fever with the first dose. You get medicines beforehand, and nurses watch you closely. Treatment can lower your defenses for months. Wash your hands often, and call right away for a fever. Feeling very tired is common. Short walks and rest can help. Nausea medicine works best taken before you feel sick. Some immune treatments can cause fever or confusion. Caregivers should watch for this and call right away. We have a whole side effects guide on this site.

Living well with it

Last, let's talk about living well. Follicular lymphoma is often a long-term condition. You may have long stretches with no treatment at all. Waiting can feel hard, and that is normal. Tell your team about new lumps, fevers, sweats, or weight loss. Ask which vaccines you need and when. Staying active and not smoking both help. Support groups and counselors can help you and your family. Call right away for a fever, trouble breathing, or new confusion. If it feels very bad, call 911. Also see our Screening, prevention and survivorship section.

You did great today. That was a lot, and you took it one step at a time. Remember, follicular lymphoma is often a long road with many good options along the way. Write down your questions and bring them to your next visit. Call your care team any time something worries you. You are not alone in this.

Call your care team right away if you have

Fever of 100.4 F (38 C) or higher, or chills
Confusion, trouble speaking, shaking, or being very hard to wake up, especially after CAR T-cell therapy or a bispecific antibody
Trouble breathing, chest pain, or a fast heartbeat
Chills, wheezing, or swelling of the lips or throat during or after an antibody infusion
Swelling of the face, neck, or arms, or new trouble swallowing
A lump that grows quickly over days to weeks, or new belly pain or swelling
Bleeding that will not stop, or new bruises or tiny red spots on the skin
Swelling, pain, or warmth in one leg, which can be a blood clot
Vomiting or diarrhea that will not stop, or you cannot keep fluids down
Yellow skin or eyes

Side effects: what helps

Sources

Quick answers

What is follicular lymphoma?: Follicular lymphoma is a cancer of B cells. B cells are white blood cells that make antibodies to fight infection. They live in your lymph nodes, spleen, bone marrow, and blood. It is the most common slow-growing (indolent) lymphoma. It gets its name because the cancer cells gather in round clusters, called follicles, inside the lymph node. It is most common in people in their 60s.
When should I call my care team?: Fever of 100.4 F (38 C) or higher, or chills; Confusion, trouble speaking, shaking, or being very hard to wake up, especially after CAR T-cell therapy or a bispecific antibody; Trouble breathing, chest pain, or a fast heartbeat; Chills, wheezing, or swelling of the lips or throat during or after an antibody infusion; Swelling of the face, neck, or arms, or new trouble swallowing; A lump that grows quickly over days to weeks, or new belly pain or swelling; Bleeding that will not stop, or new bruises or tiny red spots on the skin; Swelling, pain, or warmth in one leg, which can be a blood clot; Vomiting or diarrhea that will not stop, or you cannot keep fluids down; Yellow skin or eyes.

Last updated: 2026-10-27. Medically reviewed by Veli Bakalov, MD, medical oncologist (October 2026). General education from Step by Step, the patient portal of HemeOncBuddy.