Hodgkin Lymphoma

What is childhood Hodgkin lymphoma?

Childhood Hodgkin lymphoma is a disease in which malignant (cancer) cells form in the lymph system. The lymph system is part of the body's immune system and contains these body parts:

• Lymph: Colorless, watery fluid that travels through the lymph system and carries white blood cells called lymphocytes. Lymphocytes protect the body against infections and the growth of tumors.
• Lymph vessels: A network of thin tubes that collect lymph from different parts of the body and return 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.
• Spleen: An organ that makes lymphocytes, filters the blood, stores blood cells, and destroys old blood cells. The spleen is on the left side of the abdomen near the stomach.
• Thymus: An organ in which lymphocytes grow and multiply. The thymus is in the chest behind the breastbone.
• Tonsils: Two small masses of lymph tissue at the back of the throat. The tonsils make lymphocytes. 
• Bone marrow: The soft, spongy tissue in the center of large bones. Bone marrow makes white blood cells, red blood cells, and platelets.

Because lymph tissue is found throughout the body, Hodgkin lymphoma can start in almost any part of the body and spread to almost any tissue or organ in the body. 

What types of lymphomas are there?

Lymphomas are divided into two general types: Hodgkin lymphoma and non-Hodgkin lymphoma. 

Hodgkin lymphoma can occur in both children and adults; however, treatment for children may be different than treatment for adults. There are two types of childhood Hodgkin lymphoma:

• Classical Hodgkin lymphoma, which is divided into four subtypes based on how the cancer cells look under a microscope:
  • Lymphocyte-rich classical Hodgkin lymphoma
  • Nodular sclerosis Hodgkin lymphoma
  • Mixed cellularity Hodgkin lymphoma
  • Lymphocyte-depleted Hodgkin lymphoma.
• Nodular lymphocyte-predominant Hodgkin lymphoma

What are the risk factors for childhood Hodgkin lymphoma?

Certain factors may increase a child’s risk of developing Hodgkin lymphoma, although most children with these risk factors will never develop the disease. A risk factor is anything that increases the likelihood of developing a condition, but having a risk factor does not mean a child will develop cancer. Factors associated with an increased risk of childhood Hodgkin lymphoma include:

• Being between the ages of 15 and 19. At these ages, Hodgkin lymphoma is slightly more common in girls than in boys. In children younger than 5 years, it is more common in boys than in girls.
• Being infected with the Epstein-Barr virus.
• Having a brother or sister with Hodgkin lymphoma

What are the symptoms of childhood Hodgkin lymphoma?

Possible signs of childhood Hodgkin lymphoma include swollen lymph nodes, fever, night sweats, and weight loss. These and other symptoms may be caused by childhood Hodgkin lymphoma or by other conditions. A doctor should be consulted if any of the following problems occur: 

• Painless, swollen lymph nodes in the neck, chest, underarm, or groin
• Fever
• Night sweats
• Weight loss for no known reason
• Itchy skin

What tests will the doctor use to diagnose Hodgkin lymphoma?

• 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.
• Lymph node biopsy: The removal of all or part of a lymph node. One of the following types of biopsies may be done:
• Excisional biopsy: The removal of an entire lymph node.
• Incisional biopsy: The removal of part of a lymph node.
• Core biopsy: The removal of tissue from a lymph node using a wide needle.
• Fine-needle aspiration (FNA) biopsy: The removal of tissue from a lymph node using a thin needle. A pathologist views the tissue under a microscope to look for cancer cells, especially Reed-Sternberg cells. Reed-Sternberg cells are common in classical Hodgkin lymphoma.
• Chest x-ray: An x-ray of the organs and bones inside the chest. An x-ray is a type of energy beam that can go through the body and onto film, making a picture of areas inside the body.
• CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside the body, taken from different angles. The pictures are made by a computer linked to an x-ray machine. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography. 
• Complete blood count (CBC): A procedure in which a sample of blood is drawn and checked for the following:
  • The number of red blood cells, white blood cells, and platelets.
  • The amount of hemoglobin (the protein that carries oxygen) in the red blood cells.
  • The portion of the blood sample made up of red blood cells.
• Sedimentation rate: A procedure in which a sample of blood is drawn and checked for the rate at which the red blood cells settle to the bottom of the test tube.
• Blood chemistry studies: A procedure in which a blood sample is checked to measure the amounts of certain substances released into the blood by organs and tissues in the body. An unusual (higher or lower than normal) amount of a substance can be a sign of disease in the organ or tissue that makes it.
• Positron Emission Tomography scan (PET scan): A procedure to find malignant tumor cells in the body. A small amount of radioactive glucose (sugar) is injected into a vein. The PET scanner rotates around the body and makes a picture of where glucose is being used in the body. Malignant tumor cells show up brighter in the picture because they are more active and take up more glucose than normal cells do.
• Immunophenotyping: A test in which the cells in a sample of blood or bone marrow are looked at under a microscope to find out the type of malignant (cancerous) lymphocytes that are causing the lymphoma.

What influences the prognosis of a patient?

Most children and adolescents with newly diagnosed Hodgkin lymphoma achieve excellent outcomes. The likelihood of recovery and the treatment approach depend on several factors, including the following.

• The stage of the cancer
• The size of the tumor and how quickly it shrinks after initial treatment
• The patient's symptoms when diagnosed
• Certain features of the cancer cells
• Whether the cancer is newly diagnosed, does not respond to initial treatment, or has recurred (come back)
• The child's age and gender
• The risk of long-term side effects