Lymphoma is cancer that starts in the lymph system, the network of vessels and nodes that filters fluid throughout your body

Lymphoma begins when cells in your lymph nodes or other lymphoid tissues grow abnormally and multiply out of control. Your lymph system is part of your immune system — it contains white blood cells called lymphocytes that normally fight infection. When these cells become cancerous, they crowd out healthy cells and can spread to other parts of your body.

There are two main categories: Hodgkin lymphoma and non-Hodgkin lymphoma. The difference lies in the type of lymphocyte involved and how the cancer cells look under a microscope. Non-Hodgkin lymphoma is more common, accounting for about 90% of all lymphoma cases. Both types can develop at any age, though some forms are more common in children and others in older adults.

Key Takeaways

  • Lymphoma starts in lymphocytes — white blood cells in your lymph nodes, spleen, or bone marrow — and causes them to multiply abnormally.
  • Hodgkin lymphoma and non-Hodgkin lymphoma are the two main types, distinguished by which lymphocytes are affected and how they appear under a microscope.
  • Common early signs include swollen lymph nodes (usually in the neck, armpit, or groin), fever, night sweats, and unexplained weight loss.
  • Diagnosis requires a biopsy — a sample of tissue from an affected lymph node examined in a lab — not just imaging or blood tests alone.
  • Treatment options include chemotherapy, radiation, immunotherapy, and targeted drugs, often used in combination depending on the type and stage.

How Lymphoma Develops and Spreads

Lymphoma develops when a single lymphocyte mutates and begins dividing repeatedly. This mutated cell passes its abnormality to its copies, creating a clone of cancer cells. Over time, these cells accumulate in lymph nodes, making them swell. Unlike some cancers that form a single tumor, lymphoma often affects multiple nodes at once.

The cancer can spread beyond the lymph system to other organs — the liver, spleen, bone marrow, lungs, or digestive tract. This spread is called staging, and doctors use it to describe how far the cancer has advanced. Stage 1 means cancer is in one lymph node region. Stage 4 means it has reached organs outside the lymph system. Where the cancer spreads affects treatment decisions and outlook.

Symptoms That May Appear

Many people notice swollen lymph nodes first — usually in the neck, under the arms, or in the groin. These nodes may feel firm, rubbery, and painless. Some people have no other symptoms for months or even years. Others develop what doctors call B symptoms: fever (often in the afternoon or evening), drenching night sweats, and unintended weight loss of 10% or more of body weight over a few months.

Other signs can include fatigue, loss of appetite, itching skin, or a persistent cough if the cancer involves the chest. Because these symptoms are common to many conditions — infections, other cancers, autoimmune diseases — they do not mean you have lymphoma. But if swollen nodes persist for more than two weeks, or if you have fever and night sweats together, it is worth mentioning to your doctor.

Hodgkin Lymphoma vs. Non-Hodgkin Lymphoma

Hodgkin lymphoma involves a specific type of abnormal cell called a Reed-Sternberg cell, visible only under a microscope. It tends to spread in an orderly way from one lymph node group to the next. It is less common than non-Hodgkin lymphoma but often has a better outlook, especially when caught early. It can occur at any age but has two peaks: one in the 20s and another after age 55.

Non-Hodgkin lymphoma is a group of many different subtypes, each with different behavior and treatment. It can spread randomly to distant nodes and organs rather than in an orderly pattern. Some non-Hodgkin subtypes grow slowly (indolent), while others grow quickly (aggressive). The specific subtype matters greatly for treatment and prognosis, which is why a biopsy and lab analysis are essential.

How Doctors Diagnose Lymphoma

Diagnosis starts with a physical exam and blood tests, but these alone cannot confirm lymphoma. A doctor must perform a biopsy — removing a sample of tissue from a swollen lymph node and examining it under a microscope. A pathologist looks for cancer cells and determines the specific type. This is the only way to know for certain whether swollen nodes are lymphoma or something else.

After biopsy confirms lymphoma, doctors order imaging tests — usually a CT scan or PET scan — to see whether cancer is present in other parts of your body. They may also do a bone marrow biopsy to check if cancer has reached the marrow. These tests together determine the stage, which guides treatment decisions. Staging can take several weeks because multiple tests are needed.

Treatment Options and How They Work

Chemotherapy uses drugs to kill cancer cells throughout the body. It is often the first treatment for both Hodgkin and non-Hodgkin lymphoma. Chemotherapy is usually given in cycles — a period of treatment followed by recovery time — over several months. Side effects can include nausea, hair loss, fatigue, and increased infection risk because the drugs also affect healthy blood cells.

Radiation therapy uses high-energy beams to kill cancer cells in a specific area. It may be used alone for early-stage disease or combined with chemotherapy. Immunotherapy drugs help your immune system recognize and attack cancer cells. Targeted therapy drugs attack specific mutations or proteins on lymphoma cells. Many people receive a combination of these treatments depending on the type, stage, and how the cancer responds to initial treatment.

Survival Rates and Long-Term Outlook

Outlook varies widely depending on the type of lymphoma, stage at diagnosis, age, and overall health. Hodgkin lymphoma generally has better survival rates than many non-Hodgkin subtypes, especially when diagnosed early. Some non-Hodgkin subtypes that grow slowly may not need immediate treatment and can be monitored over time. Others that grow quickly require urgent treatment but may respond well to chemotherapy.

Many people with lymphoma go into remission — a state where cancer is no longer detectable. Some remain in remission for years or decades. Others may have the cancer return and require additional treatment. Your doctor can discuss the specific outlook for your type and stage based on current research and your individual situation. Support groups and survivorship programs can help during and after treatment.

Frequently Asked Questions

Is lymphoma the same as leukemia?

No. Lymphoma is cancer of lymph nodes and lymphoid tissues. Leukemia is cancer of blood cells that starts in the bone marrow. Both involve white blood cells, but they develop in different places and are treated differently. A biopsy shows which one is present.

Can you get lymphoma from someone else?

No, lymphoma is not contagious. You cannot catch it from another person. It develops when your own cells mutate. Some infections (like Epstein-Barr virus or hepatitis C) may increase risk in some people, but the infection itself does not cause lymphoma in most infected people.

What causes lymphoma?

The exact cause is usually unknown. Risk factors include age, a weakened immune system, certain infections, autoimmune diseases, and family history. Exposure to certain chemicals or radiation may increase risk. Most people with risk factors never develop lymphoma, and many people with lymphoma have no known risk factors.

Does lymphoma always require treatment right away?

Not always. Some slow-growing non-Hodgkin subtypes may be monitored without immediate treatment — an approach called "watch and wait." Your doctor will discuss whether treatment should start now or whether monitoring is safe. Aggressive types usually require prompt treatment.

Can lymphoma come back after treatment?

Some people remain in remission indefinitely. Others may have a recurrence months or years later. If lymphoma returns, additional treatment options are available, including different chemotherapy drugs, clinical trials, or stem cell transplant. Your doctor will discuss the plan if this happens.