Overview
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
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.
Causes
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.
Risk factors
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.
Complications
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.