Hodgkin lymphoma is also called Hodgkin disease. It's a type of cancer that starts in the lymphatic system. The lymphatic system is part of the immune system. It helps to fight diseases and infections. The lymphatic system also helps balance fluids in different parts of the body.

Hodgkin lymphoma causes abnormal growth of the cells in the lymphatic system. Over time, the body is less able to fight infection and the lymph nodes swell. Hodgkin lymphoma cells can also spread (metastasize) to other organs and tissues.

It's a rare disease in children under age 5. But Hodgkin lymphoma is the most common cancer diagnosed in teens ages 15 to 19. There are two main childhood Hodgkin lymphoma types:

• Classic Hodgkin lymphoma
• Nodular lymphocyte-predominant

Classic Hodgkin lymphoma is the most common type. It occurs mostly in teens. Nodular lymphocyte-predominant Hodgkin lymphoma is not as common. It occurs mostly in children 10 years of age or younger.

The exact cause of Hodgkin lymphoma is not known. Having a weak immune system and some viral infections may increase a child's risk of having Hodgkin lymphoma. Conditions that are linked to Hodgkin lymphoma are listed below. But because Hodgkin lymphoma is so rare, the risk is still very low.

• Epstein-Barr virus infection, which causes mononucleosis (mono)
• HIV infection, the virus that causes AIDS
• Having a family history of Hodgkin lymphoma
• Certain immune system diseases
• Having a weakened immune system after an organ transplant or from medicine given to stop the organ from being rejected by the body

Symptoms tend to be a bit different in each child. It depends on where the Hodgkin lymphoma starts and the size of the cancer. They can include:

• Painless swelling of the lymph nodes in the neck, underarm, groin, or chest.
• Trouble breathing.
• Coughing.
• B symptoms: fever for no known reason, drenching night sweats, and weight loss for no known reason.
• Tiring easily (fatigue).
• Loss of appetite.
• Itching skin.
• Frequent infections.

The symptoms of Hodgkin lymphoma are a lot like those of other health conditions. It's important to take your child to a doctor if you notice these symptoms. Only a doctor can tell if your child has cancer.

Your child's doctor will ask about your child's medical history and symptoms. A physical exam will be done. Some tests might be done, too, such as:

• Blood and urine tests. These can be used to get an idea of your child's overall health and organ function. Certain changes can be signs of disease.
• Chest X-ray. The chest X-ray shows the heart, lungs, and other parts of the chest.
• Lymph node biopsy. A tiny piece of tissue (called a sample) can be taken out of a swollen lymph node, or the whole lymph node may be removed. It's sent to a lab and tested for cancer cells. A lymph node biopsy is needed to diagnose Hodgkin lymphoma.
• CT scan. This may be done for the neck, abdomen, chest, pelvis, or a combination. A CT scan uses a series of X-rays taken from different angles and a computer to make detailed 3-D pictures of the inside of the body.
• MRI scan. An MRI uses large powerful magnets, radio waves, and a computer to make detailed pictures of the inside of the body. This test is often used to check the brain and spinal cord. Or it may be used if the results of an X-ray or CT scan are unclear.
• Positron emission tomography (PET) scan. For this test, a radioactive sugar is injected into the bloodstream. Cancer cells use the sugar faster than normal cells, so it collects in cancer cells. A special camera is used to see where the radioactive sugar is in the body. A PET scan can sometimes show cancer cells in different parts of the body, even when they can't be seen on other tests. This test is often done along with a CT scan. This is called a PET/CT scan.
• Bone marrow aspiration or biopsy. Bone marrow is the thick liquid in the center of some bones. It's where blood cells are made. A small amount of bone marrow may be taken out with a large needle. This is called aspiration. Or solid bone marrow tissue may be removed with a needle. This is called a core biopsy. Bone marrow is usually taken from the hip bone. This test may be done to see if cancer cells have reached the bone marrow. It may be done when the cancer is advanced, if there are B symptoms present, or for both reasons.

Part of diagnosing cancer is called staging. The stage of a cancer is how much cancer there is and how far it has spread in the body. The stage is one of the most important things to know when deciding how to treat the cancer. Talk with your child's doctor about the stage of your child's cancer.

There are different ways to stage Hodgkin lymphoma. The system commonly used is the Lugano classification. It uses the Roman numerals I (1), II (2), III (3), or IV (4). The higher the number, the more advanced the cancer is. Letters can be added to the Roman numerals to give even more information.

Here is what the numbers mean:

• Stage I. The cancer is in one lymph node region or in one organ or site outside the lymphatic system.
• Stage II. Is one of these:
  • The cancer is in two or more lymph node regions on the same side of the diaphragm. (This is the thin sheet of muscle that separates the chest and abdomen.)
  • Or the cancer has spread from one lymph node region into a nearby organ outside the lymphatic system, but on the same side of the diaphragm.
• Stage III. The cancer is in lymph node regions on both sides of the diaphragm (above and below). It might also be localized in an organ outside the lymphatic system or in the spleen.
• Stage IV. The cancer is in the lymphatic system and has widely spread to one or more organs outside the lymphatic system (metastasis) and possibly into nearby lymph nodes. Or the cancer has spread to one organ outside the lymphatic system and is also in distant lymph nodes.

Letters that might be added are:

• A (for asymptomatic) means your child does not have B symptoms, including those of fevers, night sweats, or weight loss for no known reason.
• B is for B symptoms, which are fever, night sweats, or weight loss for no known reason. If B is used, it means your child has these symptoms.
• E is used if lymphoma cells are found in tissues or organs outside your child's lymphatic system.
• S is for spleen. It's used if lymphoma cells have been found in your child's spleen.

Most children with Hodgkin lymphoma can be cured. Treatment choices depend on the stage and other factors. Sometimes, more than one kind of treatment is used. Hodgkin lymphoma can be treated with any of the below:

• Chemotherapy. These strong medicines kill cancer cells or stop them from growing. They may be given right into the blood through a vein (I.V.), injected (as a shot), or taken by mouth. Usually more than one chemotherapy medicine is given. This is called combination chemotherapy.
• Radiation therapy. These are high-energy beams of X-rays or other types of radiation. They're used to kill cancer cells or stop them from growing.
• High-dose chemotherapy with a stem cell transplant. Young blood cells (stem cells) are taken from the child or from someone else (donor). This is followed by high doses of chemotherapy. These doses damage the bone marrow. After the chemo, the stem cells are replaced. These go back into the bone marrow to make new, healthy blood cells.
• Targeted therapy. These medicines target changes on or in the lymphoma cells that make them different from healthy cells. They can help kill cancer cells with less damage to normal cells. Types of targeted therapy are monoclonal antibody therapy or proteasome inhibitor therapy.
• Immunotherapy. This therapy uses the child's immune system to fight the cancer. A type of immunotherapy is immune checkpoint inhibitor therapy. Other types of immunotherapy are being researched.
• Surgery. This treatment to remove as much of the tumor as possible may be used for newly diagnosed localized nodular lymphocyte-predominant Hodgkin lymphoma.
• Supportive care. Hodgkin lymphoma and its treatment can cause side effects. Medicines and many other treatments can be used for pain, fever, infection, and nausea and vomiting.
• Clinical trials. Most children with Hodgkin lymphoma are treated in clinical trials. Taking part in a clinical trial means your child gets the best treatment available today, and might also get new treatments that are thought to be even better. Before starting treatment, ask your child's doctor if there are any treatments being tested that may work well for your child.

Your child will need follow-up care during and after treatment to:

• Check on your child's response to the treatment.
• Manage the side effects of treatment.
• Look for returning or spreading cancer.

Some treatments may be hard on your child, but they increase the chance of your child living a long time. Discuss the side effects of treatment with your child's doctor.

With any cancer, how well a child is expected to recover (prognosis) varies. Keep in mind:

• Getting medical treatment right away is important for the best outcomes.
• Ongoing follow-up care during and after treatment is needed.
• New treatments are being tested to improve outcome and to reduce side effects.

Possible complications depend on the type and stage of the lymphoma, and the type of treatment needed to treat the disease. Possible complications include:

• Increased risk of infection.
• Heart disease.
• Lung problems.
• An increased chance of having other cancers later in life.
• Fertility problems.
• Delayed growth and development.
• Changes in thinking, memory, and learning.
• An increased risk of bleeding.
• An increased risk for infection.
• Nausea and vomiting.
• Diarrhea.
• Poor appetite.
• Sores in the mouth.
• Hair loss.

Many side effects can be treated to keep them from getting worse. There may even be things you can do to help prevent some of them. Most side effects go away over time after treatment ends. Still, some side effects can happen much later in life, and some can be permanent. Talk with your child's doctors about what symptoms to watch for and when to call them.

You can help your child manage their treatment in many ways. For example:

• Get emotional support for your child. Find a counselor, psychologist, or child support group that can help.
• Make sure your child attends all follow-up appointments.
• Your child may have trouble eating. A dietitian may be able to help.
• Your child may be very tired. They will need to balance rest and activity. Encourage your child to get some exercise. This is good for overall health. And it may help to reduce tiredness. Ask your child's doctor what exercises are safe for your child.

Contact the doctor if your child has:

• Symptoms that get worse.
• New symptoms.
• Side effects that don't get better with treatment.

Talk to your doctor about when you need to call them, what number to call, and what you should do if you have problems after office hours or on weekends or holidays.

• Hodgkin lymphoma is a type of cancer in the lymphatic system.
• Most children with Hodgkin lymphoma are treated successfully and cured.
• Symptoms of Hodgkin lymphoma include painless swelling of the lymph nodes in the neck, underarm, groin, or chest, trouble breathing, night sweats, fever, and feeling tired.
• A lymph node biopsy is needed to diagnose Hodgkin lymphoma.
• Treatment may include medicines such as chemotherapy, targeted therapy, or immunotherapy, radiation therapy, a stem cell transplant, and surgery.

Tips to help you get the most from a visit to your child's doctor:

• Know the reason for the visit and what you want to happen.
• Before your visit, write down questions you want answered.
• At the visit, write down the name of a new diagnosis and any new medicines, treatments, or tests. Also write down any new instructions your doctor gives you for your child.
• Know why a new medicine or treatment is prescribed and how it will help your child. Also know what the side effects are and when they should be reported.
• Ask if your child's condition can be treated in other ways.
• Know why a test or procedure is recommended and what the results could mean.
• Know what to expect if your child does not take the medicine or have the test or procedure.
• If your child has a follow-up appointment, write down the date, time, and purpose for that visit.
• Know how you can contact your child's doctor after office hours and on weekends and holidays. This is important if your child becomes ill and you have questions or need advice.