Lymphedema is the build-up of fluid in soft body tissues when the lymph system is damaged or blocked.

Lymphedema occurs when the lymph system is damaged or blocked. Fluid builds up in soft body tissues and causes swelling. It is a common problem that may be caused by cancer and cancer treatment. Lymphedema usually affects an arm or leg, but it can also affect other parts of the body. Lymphedema can cause long-term physical, psychological, and social problems for patients.

The lymph system is a network of lymph vessels, tissues, and organs that carry lymph throughout the body.

The parts of the lymph system that play a direct part in lymphedema include the following:

• Lymph: A clear fluid that contains lymphocytes (white blood cells) that fight infection and the growth of tumors. Lymph also contains plasma, the watery part of the blood that carries the blood cells.
• Lymph vessels: A network of thin tubes that helps lymph flow through the body and returns it to the bloodstream.
• Lymph nodes: Small, bean-shaped structures that filter lymph and store white blood cells that help fight infection and disease. Lymph nodes are located along the network of lymph vessels found throughout the body. Clusters of lymph nodes are found in the underarm, pelvis, neck, abdomen, and groin.

The spleen, thymus, tonsils, and bone marrow are also part of the lymph system but do not play a direct part in lymphedema.

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Anatomy of the lymph system, showing the lymph vessels and lymph organs including lymph nodes, tonsils, thymus, spleen, and bone marrow. Lymph (clear fluid) and lymphocytes travel through the lymph vessels and into the lymph nodes where the lymphocytes destroy harmful substances. The lymph enters the blood through a large vein near the heart.

Lymphedema occurs when lymph is not able to flow through the body the way that it should.

When the lymph system is working as it should, lymph flows through the body and is returned to the bloodstream.

• Fluid and plasma leak out of the capillaries (smallest blood vessels) and flow around body tissues so the cells can take up nutrients and oxygen.
• Some of this fluid goes back into the bloodstream. The rest of the fluid enters the lymph system through tiny lymph vessels. These lymph vessels pick up the lymph and move it toward the heart. The lymph is slowly moved through larger and larger lymph vessels and passes through lymph nodes where waste is filtered from the lymph.
• The lymph keeps moving through the lymph system and collects near the neck, then flows into one of two large ducts:
  • The right lymph duct collects lymph from the right arm and the right side of the head and chest.
  • The left lymph duct collects lymph from both legs, the left arm, and the left side of the head and chest.
• These large ducts empty into veins under the collarbones, which carry the lymph to the heart, where it is returned to the bloodstream.

When part of the lymph system is damaged or blocked, fluid cannot drain from nearby body tissues. Fluid builds up in the tissues and causes swelling.

There are two types of lymphedema.

Lymphedema may be either primary or secondary:

• Primary lymphedema is caused by the abnormal development of the lymph system. Symptoms may occur at birth or later in life.

• Secondary lymphedema is caused by damage to the lymph system. The lymph system may be damaged or blocked by infection, injury, cancer, removal of lymph nodes, radiation to the affected area, or scar tissue from radiation therapy or surgery.

This summary is about secondary lymphedema in adults that is caused by cancer or cancer treatment.

Possible signs of lymphedema include swelling of the arms or legs.

Other conditions may cause the same symptoms. A doctor should be consulted if any of the following problems occur:

• Swelling of an arm or leg, which may include fingers and toes.
• A full or heavy feeling in an arm or leg.
• A tight feeling in the skin.
• Trouble moving a joint in the arm or leg.
• Thickening of the skin, with or without skin changes such as blisters or warts.
• A feeling of tightness when wearing clothing, shoes, bracelets, watches, or rings.
• Itching of the legs or toes.
• A burning feeling in the legs.
• Trouble sleeping.
• Loss of hair.

Daily activities and the ability to work or enjoy hobbies may be affected by lymphedema.

These symptoms may occur very slowly over time or more quickly if there is an infection or injury to the arm or leg.

Cancer and its treatment are risk factors for lymphedema.

Lymphedema can occur after any cancer or treatment that affects the flow of lymph through the lymph nodes, such as removal of lymph nodes. It may develop within days or many years after treatment. Most lymphedema develops within three years of surgery. Risk factors for lymphedema include the following:

• Removal and/or radiation of lymph nodes in the underarm, groin, pelvis, or neck. The risk of lymphedema increases with the number of lymph nodes affected. There is less risk with the removal of only the sentinel lymph node (the first lymph node to receive lymphatic drainage from a tumor).
• Being overweight or obese.
• Slow healing of the skin after surgery.
• A tumor that affects or blocks the left lymph duct or lymph nodes or vessels in the neck, chest, underarm, pelvis, or abdomen.
• Scar tissue in the lymph ducts under the collarbones, caused by surgery or radiation therapy.

Lymphedema often occurs in breast cancer patients who had all or part of their breast removed and axillary (underarm) lymph nodes removed. Lymphedema in the legs may occur after surgery for uterine cancer, prostate cancer, lymphoma, or melanoma. It may also occur with vulvar cancer or ovarian cancer.

Tests that examine the lymph system are used to diagnose lymphedema.

It is important to make sure there are no other causes of swelling, such as infection or blood clots. The following tests and procedures may be used to diagnose lymphedema:

• Physical exam and history: An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient’s health habits and past illnesses and treatments will also be taken.

• Lymphoscintigraphy: A procedure used to make pictures (called scintigrams) of the lymph system to check for blockages or anything else that seems unusual. A radioactive substance is injected under the skin, between the first and second fingers or toes of each hand or foot. The substance is taken up by the lymph vessels and detected by a scanner. The scanner makes images of the flow of the substance through the lymph system on a computer screen.

• MRI (magnetic resonance imaging): A procedure that uses a magnet, radio waves, and a computer to make a series of detailed pictures of areas inside the body. This procedure is also called nuclear magnetic resonance imaging (NMRI).

The swollen arm or leg is usually measured and compared to the other arm or leg. Measurements are taken over time to see how well treatment is working.

A grading system is also used to diagnose and describe lymphedema. Grades 1, 2, 3, and 4 are based on size of the affected limb and how severe the signs and symptoms are.

Stages may be used to describe lymphedema.

• Stage I: The limb (arm or leg) is swollen and feels heavy. Pressing on the swollen area leaves a pit (dent). This stage of lymphedema may go away without treatment.
• Stage II: The limb is swollen and feels spongy. A condition called tissue fibrosis may develop and cause the limb to feel hard. Pressing on the swollen area does not leave a pit.
• Stage III: This is the most advanced stage. The swollen limb may be very large. Stage III lymphedema rarely occurs in breast cancer patients. Stage III is also called lymphostatic elephantiasis.