Hodgkin lymphoma (HL), one of the most curable forms of cancer, was named for Thomas Hodgkin, a British pathologist. In 1832, Dr. Hodgkin described several cases of people with symptoms of a cancer involving the lymph nodes. This disease was called “Hodgkin’s disease” for about 170 years. It was officially renamed “Hodgkin lymphoma” in the late 20th century—when it became evident that the disease results from an injury to the DNA of a lymphocyte (type of white blood cell). The damage to the DNA is acquired (occurs after birth) rather than inherited. The altered DNA in the lymphocyte produces a cancerous change that— if untreated—results in the uncontrolled growth of the cancerous lymphocytes. The accumulation of the cancerous lymphocytes results in the tumor masses that are found in the lymph nodes and other sites in the body.
HL is distinguished from other types of lymphoma by the presence of “Reed-Sternberg cells” (named for the scientists who first identified them). Reed-Sternberg cells are usually B cells and have differences and variations to them. The frequency with which these cells are seen and the variations observed help determine a patient’s subtype. Other cells associated with the disease are called “Hodgkin cells.”
Lymphomas are cancers that start in white blood cells called lymphocytes. There are 2 main types of lymphoma:
● Hodgkin lymphoma (HL)
● Non-Hodgkin lymphoma (NHL)
They behave, spread, and respond to treatment differently, so it’s important for you to know which one you have.
The lymph system
To understand what Hodgkin lymphoma is, it helps to know about the lymph system (also known as the lymphatic system). The lymph system is part of the immune system, which helps fight infections and some other diseases. The lymph system also helps control the flow of fluids in the body.
The lymph system is made up mainly of cells called lymphocytes, a type of white blood cell. There are 2 main types of lymphocytes:
● B lymphocytes (B cells): B cells make proteins called antibodies to help protect the body from germs (bacteria and viruses).
● T lymphocytes (T cells): There are many types of T cells. Some T cells destroy germs or abnormal cells in the body. Other T cells help boost or slow the activity of other immune system cells.
Hodgkin lymphoma usually starts in B lymphocytes.
Start and spread of Hodgkin lymphoma
Lymph tissue is in many parts of your body, so Hodgkin lymphoma can start almost anywhere.
The major sites of lymphoid tissue are:
Lymph nodes: Lymph nodes are bean-sized collections of lymphocytes and other immune system cells. They’re found throughout the body, including inside the chest, abdomen (belly), and pelvis. They’re connected to each other by a system of lymphatic vessels.
Lymph vessels: A network of tiny tubes (a lot like blood vessels) that connect lymph nodes and carry immune cells in a clear fluid called lymph. Lymph is collected from around the body and put into the bloodstream.
Spleen: The spleen is an organ that’s under the lower ribs on your left side. The spleen is part of your immune system. It makes lymphocytes and other immune system cells. It also stores healthy blood cells and filters out damaged blood cells, bacteria, and cell waste.
Bone marrow: The bone marrow is the liquid, spongy tissue inside certain bones. New blood cells (including some lymphocytes) are made there.
Thymus: The thymus is a small organ behind the upper part of the breastbone and in front of the heart. It’s important for T lymphocyte development.
Adenoids and tonsils: These are collections of lymph tissue in the back of your throat. They help make antibodies against germs that are breathed in or swallowed.
Digestive tract: The stomach, intestines, and many other organs also have lymph tissue.
Although Hodgkin lymphoma can start almost anywhere, most often it starts in lymph nodes in the upper part of the body. The most common sites are in the chest, neck, or under the arms.
Hodgkin lymphoma most often spreads through the lymph vessels from lymph node to lymph node. Rarely, late in the disease, it can invade the bloodstream and spread to other parts of the body, such as the liver, lungs, and/or bone marrow.
Types of Hodgkin lymphoma
Different types of Hodgkin lymphoma can grow and spread differently and may be treated differently.
Classic Hodgkin lymphoma
Classic Hodgkin lymphoma (cHL) accounts for more than 9 in 10 cases of Hodgkin lymphoma in developed countries.
The cancer cells in cHL are called Reed-Sternberg cells. These cells are usually an abnormal type of B lymphocyte. Enlarged lymph nodes in people with cHL usually have a small number of Reed-Sternberg cells with a lot of normal immune cells around them. These other immune cells cause most of the swelling in the lymph nodes.
Classic HL has 4 subtypes:
Nodular sclerosis Hodgkin lymphoma or NSCHL: This is the most common type of Hodgkin disease in developed countries. It accounts for about 7 out of 10 cases. It’s most common in teens and young adults, but it can occur in people of any age. It tends to start in lymph nodes in the neck or chest. Mixed cellularity
● Hodgkin lymphoma or MCCHL: This is the second most common type, found in about 4 out 10 cases. It’s seen mostly in people with HIV infection. It’s also found in children or the elderly. It can start in any lymph node but most often occurs in the upper half of the body.
● Lymphocyte-rich Hodgkin lymphoma: This sub-type isn’t common. It usually occurs in the upper half of the body and is rarely found in more than a few lymph nodes.
● Lymphocyte-depleted Hodgkin lymphoma: This is a rare form of Hodgkin disease. It’s seen mainly in older people and those with HIV infection. It’s more aggressive than other types of HL and likely to be advanced when first found. It’s most often in lymph nodes in the abdomen (belly) as well as in the spleen, liver, and bone marrow.
Signs and Symptoms
The most common early sign of HL is a painless swelling (enlargement) of one or more lymph nodes. The vast majority of patients with HL have affected lymph nodes in the upper part of the body—usually in the neck or upper chest. Sometimes the affected lymph node is in the armpit, abdomen or groin. There are about 600 lymph nodes in the body.
Other HL symptoms include
● Persistent fatigue
● Persistent cough and shortness of breath (if HL is located in the chest)
● sweating, especially at night (drenching sweats of the whole body, not just the neck area or chest area)
● Weight loss
● Enlarged spleen
Individuals with HL may experience pain in the lymph nodes after drinking alcohol—this is an uncommon but specific symptom.
A doctor may first order imaging tests when a patient’s medical history and physical examination suggest a possible diagnosis of HL. The imaging test(s) may show enlarged lymph nodes in the chest or abdomen or both. Tumor masses can also occur outside the lymph nodes in lung, bone or other body tissue.
Lymph node biopsy.
The diagnosis of HL can be difficult and requires an experienced hematopathologist (a doctor who specializes in diagnosing and interpreting the physical changes caused by diseases of the blood and marrow) to analyze the biopsy slides. HL can be confused with various types of non-Hodgkin lymphoma—since the treatment is different, a precise diagnosis is needed. Keep in mind that another opinion by a second hematopathologist may be necessary if there is any doubt about the diagnosis. A biopsy of an involved lymph node or other tumor site is needed to confirm the diagnosis of HL. A needle biopsy of the lymph node is usually not sufficient to make a firm diagnosis. The entire lymph node or part of the lymph node is surgically removed so that the hematopathologist has enough tissue to make a firm diagnosis.
A technique called “immunophenotyping” is sometimes used to distinguish HL from other types of lymphoma or other noncancerous conditions. The hematopathologist looks for the presence of Reed-Sternberg and Hodgkin cells to confirm a diagnosis of HL.
Doctors use physical examinations and imaging tests (also called “diagnostic radiology”) to determine the extent of the disease. This is called “staging.” Staging provides important information for treatment planning. The staging system commonly used for HL is the Modified Ann Arbor Staging System. Physical Examination and Imaging Tests. The physical examination and imaging tests help the doctor evaluate
● The location and distribution of lymph node enlargement
● Whether organs other than lymph nodes are involved
● Whether there are very large masses of tumors in one site or another. Imaging tests include
● Chest x-ray
● Computed tomography (CT) scan of the chest, abdomen and pelvis
● Magnetic resonance imaging (MRI) in select cases
● [18F] Fluorodeoxyglucose positron emission tomography (FDG-PET) (evaluates the whole body).
In many centers, patients have CT scans of the neck, chest, abdomen and pelvis— all the areas where lymph nodes are present—to see whether there are other areas of disease. The CT scan can also show whether there is involvement of the lungs, liver and other organs, which is information that is helpful in staging
Stage I: Apparent involvement of a single lymph node region or a single organ, such as bone.
Stage II: Involvement of two or more lymph node regions that are close to each other; for example, all in the neck and chest, or all in the abdomen and on the same side of the diaphragm (a thin muscle below the lungs).
Stage III: Involvement of several lymph node regions in the neck, chest and abdomen (on both sides of the diaphragm).
Stage IV: Widespread involvement of lymph nodes on both sides of the diaphragm and in other organs, such as the lungs, liver and bones.
Key Statistics for Hodgkin Lymphoma
The American Cancer Society’s estimates for Hodgkin lymphoma in the United States for 2020 are:
● About 8,480 new cases (4,690 in males and 3,790 in females)
● About 970 deaths (680 males and 400 females)
Both children and adults can develop Hodgkin lymphoma, but it’s most common in early adulthood (especially in a person’s 20s). The risk of Hodgkin lymphoma rises again in late adulthood (after age 55). Overall, the average age at the time of diagnosis is 39.
Hodgkin lymphoma is rare in children younger than 5 years old. But it’s the most common cancer diagnosed in teenagers’ ages 15 to 19 years.
Survival rates have improved in the past few decades, largely due to advances in treatment. The 5-year relative survival rate for all patients diagnosed with Hodgkin lymphoma is now about 86%. Certain factors such as the stage1 (extent) of Hodgkin lymphoma and a person’s age affect these rates