Primary mediastinal large B-cell lymphoma

Primary mediastinal large B-cell lymphoma (PMBCL) is a type of lymphoma. This type of lymphoma also is known as PMBL. Lymphoma is a cancer that affects the lymphocytes, which are a type of white blood cell. The white blood cells are part of the body's germ-fighting immune system.

There are many types of lymphoma. Lymphoma types are often divided into two categories: Hodgkin lymphoma and non-Hodgkin lymphoma. PMBCL is a type of non-Hodgkin lymphoma.

PMBCL typically forms when specialized lymphocytes in the thymus, known as B cells, undergo DNA changes and turn into cancer cells. A cell's DNA holds the instructions that tell the cell what to do and when to die. Because of these DNA changes, the cells stop dying.

They usually multiply and form a large mass within the mediastinum. The mediastinum is the space in the chest that is beneath the breastbone and between the lungs. It holds many organs including the thymus, trachea, esophagus, and heart. PMBCL is called primary mediastinal because it typically starts in the mediastinum.

PMBCL is usually a fast-growing type of cancer. Similar to other types of lymphoma, it features its own specific DNA changes that help it hide from the immune system. Treatment options may include chemotherapy, immunotherapy, radiation therapy, targeted therapy, CAR-T cell therapy and bone marrow transplant, also called bone marrow stem cell transplant.

Symptoms of primary mediastinal large B-cell lymphoma (PMBCL) may include:

• Cough.
• Voice changes such as hoarseness.
• Difficulty breathing, swallowing or both.
• Constant fever.
• Chest pain.
• Fatigue.
• Drenching night sweats.
• Weight loss without trying.

The mass also may put pressure on a large vein in the chest, called the superior vena cava. This can cause superior vena cava syndrome, which includes symptoms such as:

• Shortness of breath or difficulty breathing.
• Swelling in the face, neck, or arms
• Feeling of fullness within the head.
• Headaches.
• Confusion in severe cases.

When to see a doctor

Make an appointment with a healthcare professional if you have any symptoms that worry you or are not going away.

Primary mediastinal large B-cell lymphoma (PMBCL) typically forms when specialized white blood cells in the thymus, known as B cell lymphocytes, undergo DNA changes and turn into cancer cells. Exactly why these DNA changes happen is not known.

A cell's DNA holds the instructions that tell the cell what to do and when to die. These gene changes cause the cells to stop dying and to multiply rapidly.

The cancer cells usually spread and form masses within the mediastinum. The mediastinum is the space in the chest that is beneath the breastbone and between the lungs. It holds many organs including the thymus, trachea, esophagus and heart.

A risk factor for primary mediastinal large B-cell lymphoma (PMBCL) is being female. PMBCL tends to mainly occur in adults. Most people with PMBCL are diagnosed in their 30s and 40s.

There is no known way to prevent PMBCL.

Primary mediastinal large B-cell lymphoma (PMBCL) often forms a mass in the mediastinum. As the mass of cancer cells grows, it can press on nearby veins and organs. Complications might include:

• Superior vena cava syndrome. The superior vena cava is a large vein in the chest. If the mass presses on the vein, it may cause a number of symptoms including difficulty breathing, swelling in the face and arms, and headaches.
• Breathing issues. The mass can put pressure on the trachea and lungs. This can cause coughing, shortness of breath and a feeling of tightness in the chest, and voice changes such as hoarseness.
• Trouble swallowing. If the mass presses on the food pipe, also known as the esophagus, it can cause trouble swallowing.
• Fluid buildup. If the mass presses on the heart or blood vessels, it may cause fluid to build up around the heart and the lungs. Fluid buildup around the heart is known as a pericardial effusion. It can affect how well the heart pumps blood. Fluid also may build up around the lungs and cause breathing trouble and chest pain. This is known as pleural effusion.

A primary mediastinal large B-cell lymphoma (PMBCL) diagnosis, like other B-cell lymphoma diagnoses, often begins with a physical exam to check for swollen lymph nodes or masses in the neck, underarms and groin, and an enlarged spleen or liver. Other tests and procedures include blood tests, imaging tests and taking a sample of tissue for laboratory tests.

Biopsy

A biopsy is a procedure to remove a sample of tissue for testing in a lab. For PMBCL, a biopsy from the mass is taken. The sample is tested in a lab to look for cancer cells.

Imaging tests

An imaging test takes pictures inside the body. It can show the location and extent of PMBCL. Tests might include CT scan and positron emission tomography (PET) scan.

Testing lymphoma cells in the lab

Lymphoma cells collected from a biopsy go to a lab for testing. In the lab, specialized tests look for specific things about the cells. When viewed under a microscope, the cancer cells have a different appearance compared with healthy cells. The healthcare team uses the results to find out the type of lymphoma that you have.

To decide whether the cells are PMBCL cells, the healthcare professionals in the lab look for:

• Proteins on the surface of the cancer cells. Primary mediastinal large B-cell lymphoma cells can be identified by the presence of certain proteins on their surfaces. These proteins are known as markers.
• Changes in the cancer cells' DNA. Cancer happens when cells get changes in their DNA. A cell's DNA holds the instructions that tell a cell what to do. Gene changes cause the cancer cells to multiply rapidly.

Primary mediastinal large B-cell lymphoma (PMBCL) treatments may include chemotherapy, immunotherapy, radiation therapy, targeted therapy, CAR-T cell therapy and bone marrow transplant, also called bone marrow stem cell transplant. Your treatment depends on several factors. These include the cancer's stage, your overall health and shared decision-making with your healthcare professional.

Chemotherapy

Chemotherapy treats cancer with strong medicines. There are many types of chemotherapy medicines. Most chemotherapy medicines are given through a vein. Some come in pill form.

Chemotherapy, usually combined with immunotherapy, is often the first line of treatment for primary mediastinal large B-cell lymphoma (PMBCL). This combination is often referred to as chemoimmunotherapy.

Chemoimmunotherapy also may be an option for PMBCL that comes back after treatment, called relapsed PMBCL, or when other treatments haven't worked, known as refractory PMBCL.

Immunotherapy

Immunotherapy for cancer is a treatment with medicine that helps the body's immune system fight cancer cells. Typically, the immune system fights off diseases by attacking germs and other cells that shouldn't be in the body. Cancer cells survive by hiding from the immune system. Immunotherapy helps the immune system cells recognize and kill the cancer cells.

Radiation therapy

Radiation therapy treats cancer with powerful energy beams. The energy can come from X-rays, protons or other sources. During radiation therapy, you lie on a table while a machine moves around you. The machine directs radiation to precise points in your body.

Some people with primary mediastinal large B-cell lymphoma (PMBCL) may need radiation therapy after chemoimmunotherapy to help get rid of any remaining cancer cells. Radiation therapy can be used as part of the treatment for relapsed PMBCL. In people who can't have other treatments, radiation therapy may help ease symptoms.

Targeted therapy

Targeted therapy for cancer is a treatment that uses medicines that attack specific chemicals in the cancer cells. By blocking these chemicals, targeted treatments can cause cancer cells to die.

Targeted therapy can be used in relapsed and refractory PMBCL.

CAR-T cell therapy

Chimeric antigen receptor (CAR)-T cell therapy trains the immune system cells to fight lymphoma cells. This treatment begins with removing some white blood cells called T cells from the blood.

The cells are sent to a lab. In the lab, the cells are treated so that they make special receptors. The receptors help the cells recognize a marker on the surface of the lymphoma cells. Then the cells go back into the body similar to a blood transfusion. They find and destroy the primary mediastinal large B-cell lymphoma cells in the body.

CAR-T cell therapy may be an option for refractory or relapsed PMBCL.

Clinical trials

Clinical trials are studies of new treatments or combinations of drugs. These studies provide a chance to try the latest treatments. The risk of side effects might not be known. Ask your healthcare team if you might be a good fit for a clinical trial.

Bone marrow transplant

A bone marrow transplant, also called a bone marrow stem cell transplant, involves putting healthy bone marrow stem cells into the body. These cells replace cells hurt by chemotherapy and other treatments.

In some people, a bone marrow transplant can be used for relapsed or refractory PMBCL.

Monitoring after treatment

Primary mediastinal large B-cell lymphoma (PMBCL) has a risk of coming back after treatment, known as a relapse. After treatment, you have follow-up appointments to monitor for relapse. You may need repeat biopsies and imaging.

With time, you'll likely find what helps you cope with the uncertainty and worry of a cancer diagnosis. Until then, you may find that it helps to do the following:

Prepare to make decisions

Ask your healthcare team about your cancer, including your test results, treatment options and, if you want, your prognosis. As you learn more about primary mediastinal large B-cell lymphoma, you may become more confident in making treatment decisions.

Stay connected to friends and family

Keeping in touch with friends and family may give comfort during a time that is difficult for everyone. Your friends and family will likely ask if there's anything they can do to help you, so think of tasks you might like help with. For example, you may ask a friend to be there for you when you want to talk. You may ask for help caring for your home if you must stay in the hospital.

Find someone to talk with

Find someone you can talk to who has experience helping people facing a life-threatening illness. Ask your healthcare team to suggest a counselor, clergy member or medical social worker you can talk with about your hopes and worries.

Also ask your healthcare team about support groups in your area, or contact organizations such as the American Cancer Society, Blood Cancer United and the Lymphoma Research Foundation. Find support online through Mayo Clinic Connect, which is a community where you can connect with others for support, practical information and answers to everyday questions.

Make an appointment with a doctor or other healthcare professional if you have any symptoms that worry you.

If your healthcare professional thinks you might have primary mediastinal large B-cell lymphoma (PMBCL), you may be referred to a doctor who specializes in diseases that affect blood cells, called a hematologist. If a cancer diagnosis is made, you also may be referred to a doctor who specializes in treating cancer, called an oncologist.

Because appointments can be brief, it's a good idea to be prepared. Here's some information to help you get ready.

What you can do

• Be aware of anything you need to do ahead of time. At the time you make the appointment, be sure to ask if there's anything you need to do in advance, such as restrict your diet.
• Write down symptoms you have, including any that may not seem related to the reason for which you scheduled the appointment.
• Write down important personal information, including major stresses or recent life changes.
• Make a list of all medicines, vitamins and supplements you're taking and the doses.
• Take a family member or friend along. It can be hard to remember all the information you get during an appointment. Someone who goes with you may remember something that you missed or forgot.
• Write down questions to ask your healthcare team.

For primary mediastinal large B-cell lymphoma (PMBCL), some basic questions to ask include:

• Do I have PMBCL?
• What is the stage of my PMBCL?
• Has my PMBCL spread to other parts of my body?
• Will I need more tests?
• What are the treatment options?
• How much does each treatment prolong my life or increase my chances of a cure?
• What are the potential side effects of each treatment?

Other questions to ask include:

• How will each treatment affect my daily life?
• Is there one treatment option you believe is the best?
• What would you recommend to a friend or family member in my situation?
• Should I see a specialist?
• Are there any brochures or other printed materials that I can take with me? What websites do you recommend?
• What will determine whether I should plan for a follow-up visit?

Don't hesitate to ask other questions.

What to expect from your doctor

Be prepared to answer questions, such as:

• When did your symptoms begin?
• Do your symptoms happen all the time or do you have them now and then?
• How bad are your symptoms?
• What, if anything, seems to make your symptoms better?
• What, if anything, seems to make your symptoms worse?
• Have you had any fevers, night sweats or weight loss?
• Have you noticed any lumps, swelling or pain anywhere in your body?
• What are your biggest worries about your diagnosis or treatment?

If you're diagnosed with primary mediastinal large B-cell lymphoma (PMBCL), the next step is to find out the extent of the cancer spread. This is called the stage. Imaging and biopsies may be used to determine the stage of your PMBCL. Your healthcare team creates your treatment plan based on the stage. A higher stage means the cancer is more advanced.

The stages of PMBCL range from 1 to 4:

• Stage 1. The cancer typically affects one area.
• Stage 2. The cancer involves the mediastinum and nearby lymph nodes.
• Stage 2 bulky. Your healthcare professional also may describe your PMBCL as if the mass in the chest is larger than 10 centimeters (about 4 inches).
• Stage 3. The cancer is more advanced and involves lymph node regions on both sides of the diaphragm.
• Stage 4. The cancer has traveled to distant organs, beyond lymph nodes, such as the lungs.

The chance of surviving primary mediastinal large B-cell lymphoma (PMBCL) is different for every person. Factors include your overall health, the stage of your cancer, treatments you are receiving and how you respond to treatment.

PMBCL carries the risk of the cancer coming back after treatment, known as a relapse. Most relapses happen within the first two years after treatment.

The overall five-year survival rate for primary mediastinal large B-cell lymphoma typically exceeds 80%. This means that more than 80% of patients with a diagnosis of PMBCL are alive after five years from diagnosis.

Prognosis

The cancer prognosis tells how likely it is that the cancer can be treated successfully. Your healthcare team can get a general sense of your outlook using your primary mediastinal large B-cell lymphoma (PMBCL) stage and your overall health.

Talk with your healthcare team about your prognosis if you want to know what to expect. Members of your healthcare team can explain what they consider when thinking about your prognosis.