Diagnosing Hodgkin Lymphoma in Children
Childhood Hodgkin lymphoma is a cancer of the lymphatic system, which is composed of tissues and organs that help the body fight infection. The condition starts in a type of white blood cells, called lymphocytes, which help protect against bacteria and viruses, and spreads throughout the lymphatic system.
Named after the doctor who first recognized it, Hodgkin lymphoma differs from non-Hodgkin lymphoma in that the condition involves what are known as Reed–Sternberg cancer cells, which multiply as the cancer worsens. These two types of lymphoma progress and respond to treatment differently, and so it’s important to distinguish the type during diagnosis.
There is no known cause of this condition, but risk factors include previous infection with mononucleosis, which is caused by the Epstein-Barr virus; being HIV positive; and having a parent or sibling with a history of Hodgkin lymphoma.
Hodgkin lymphoma accounts for 4 percent of cancers diagnosed in children. Older children and adolescents are more likely to develop Hodgkin lymphoma than younger children, and the condition is more common among boys than girls. Approximately 95 percent of children with Hodgkin lymphoma can be cured.
Common symptoms include enlarged or swollen lymph nodes, chronic fever, night sweats, and unexplained weight loss. Enlarged lymph nodes typically appear in the neck or upper chest, but can also be felt as a lump in the waistline or lower abdomen, armpit, or groin. Children with Hodgkin lymphoma may exhibit subtle signs of the condition, such as fatigue, that only parents and doctors may notice.
Also, symptoms can be associated with other medical conditions, so it’s important to visit your child’s pediatrician for a checkup.
If lymphoma is suspected, our oncologists diagnose the condition by taking a medical history and performing a physical exam and certain tests. They work with pathologists to identify the type of lymphoma a child has and formulate a treatment plan.
During the initial exam, our specialists take a sample of your child’s blood to check for the number of white blood cells. This helps them rule out leukemia, the most common childhood cancer, and some other conditions that cause symptoms similar to those of Hodgkin’s lymphoma. They also check the number of red blood cells and platelets in the blood.
Low numbers of red blood cells can lead to a condition known as anemia, and low platelet numbers can prevent the blood from clotting properly.
The doctor may recommend a chest X-ray to identify enlarged lymph nodes. These are often found in the mediastinum, the area in the center of the chest that contains the esophagus and the heart, in children with Hodgkin lymphoma.
A combination CT scan and PET scan may be used to diagnose lymphoma and help differentiate between Hodgkin and non-Hodgkin lymphoma. In CT–PET scanning, two types of imaging tests provide information about the body.
With a CT scan, X-rays and a computer create three-dimensional, cross-sectional images of the body. CT scans can detect changes in the size or structure of organs, plus growths or tumors.
PET scans enable doctors to distinguish between cancerous and noncancerous tissue. In a PET scan, a small amount of a radioactive sugar is injected into a vein. The substance travels throughout the body, and a computer then creates three-dimensional images showing how different tissues metabolize the sugar. Because cancerous tissue processes sugar more quickly than healthy tissue does, cancer cells and tumors appear as brighter areas on the scan.
These scans can be performed successively by the same machine. Sedation or, for very young children, general anesthesia, may be used. If you are accompanying your child to the test, you must wear a lead apron to prevent radiation exposure. Pregnant women are advised not to be in the room while the machine is operating. The test takes about 45 minutes.
Lymph Node Biopsy
During this procedure, lymph node tissue is surgically removed for examination under a microscope. This helps doctors determine the type of lymphoma a child has. While a local anesthetic can be used in adults, typically sedation or general anesthesia is used for young children.
Your child’s doctor makes a small surgical cut, removes part of the lymph node, and closes the incision with stitches. The procedure takes about 30 minutes.
The lymph node sample is sent to a lab, where a pathologist, a doctor who specializes in analyzing cells, can identify the cell types present, including Reed–Sternberg cells. These cancer cells are found in children with Hodgkin lymphoma.
Bone Marrow Aspiration and Biopsy
After Hodgkin lymphoma is diagnosed, bone marrow aspiration and biopsy can help doctors determine how advanced the condition is—and how it should be treated. During this procedure, which is performed with sedation, your child’s doctor uses a small needle to remove a sample of bone marrow fluid from the pelvic bone in the lower back.
A hematopathologist, who specializes in analyzing cells to diagnose lymphoma, then reviews the cells under a microscope in a laboratory. If cancer cells are present in the bone marrow, more aggressive treatment is needed.