Lymphoma is a cancer that starts in white blood cells called lymphocytes, which are part of your immune system. These cells normally help your body fight infections, but in lymphoma, DNA mutations cause them to grow out of control, live longer than they should, and pile up in your lymph nodes and other tissues. The result is tumors that crowd out healthy tissue and compromise your body’s ability to defend itself.
There are two broad categories: Hodgkin lymphoma and non-Hodgkin lymphoma. Non-Hodgkin lymphoma is the more common of the two, and it encompasses dozens of subtypes that range from slow-growing to highly aggressive.
How Lymphoma Develops
Your lymphatic system is a network of vessels, nodes, and organs (including the spleen, tonsils, and thymus) that produces and circulates lymphocytes throughout your body. There are two main types of lymphocytes: B cells and T cells. Both play distinct roles in immunity, and lymphoma can arise from either one.
The cancer begins when DNA mutations alter the instructions that tell a lymphocyte how to grow and when to die. Instead of following a normal life cycle, the mutated cell divides rapidly and doesn’t die on schedule. These abnormal lymphocytes accumulate in the lymph nodes and other parts of the lymphatic system, forming tumors that crowd out healthy tissue and limit the system’s ability to function. Over time, the disease can spread beyond the lymph nodes into organs like the bone marrow, liver, or lungs.
Hodgkin vs. Non-Hodgkin Lymphoma
The distinction between the two main types comes down to a single detail visible under a microscope. Hodgkin lymphoma contains a distinctive abnormal cell called a Reed-Sternberg cell, which is larger than normal lymphocytes and often has more than one nucleus. If that cell is absent, the lymphoma is classified as non-Hodgkin.
Beyond that microscopic difference, the two types behave differently in meaningful ways:
- Cell of origin: Hodgkin lymphoma almost always arises from B cells. Non-Hodgkin lymphoma can develop from B cells, T cells, or natural killer cells.
- Where it starts: Hodgkin lymphoma typically begins in the lymph nodes of the neck, chest, groin, or armpits and tends to spread in an orderly, predictable pattern. Non-Hodgkin lymphoma can start in lymph nodes too, but is more often found outside them.
- Growth patterns: Non-Hodgkin lymphoma may be indolent (slow-growing) or aggressive (fast-growing). Some indolent forms behave more like a chronic condition, relapsing over many years.
- Prognosis: Hodgkin lymphoma is generally considered more curable. Some non-Hodgkin lymphomas carry a worse overall prognosis, though this varies widely by subtype.
Common Non-Hodgkin Subtypes
Most non-Hodgkin lymphomas develop from B cells. The two most common subtypes in adults are diffuse large B-cell lymphoma, which is usually aggressive and grows quickly, and follicular lymphoma, which is typically indolent and progresses slowly over months or years. There are many other subtypes, including mantle cell lymphoma and Burkitt lymphoma, each with its own behavior and treatment approach. The subtype matters enormously because it determines how urgently treatment needs to begin and what kind of therapy is most effective.
Symptoms to Recognize
The most common early sign of lymphoma is a painless swollen lymph node, usually in the neck, armpit, or groin. Many things cause swollen lymph nodes (a cold, for instance), so the key distinction is swelling that persists for weeks without an obvious infection.
A cluster of symptoms known as “B symptoms” often signals more advanced or aggressive disease. These include unexplained fevers, drenching night sweats (enough to soak your sheets), and unintentional weight loss of more than 10% of your body weight over six months. Other common signs include persistent fatigue, itchy skin, and shortness of breath if enlarged nodes press on structures in the chest. Because lymphoma affects immune cells directly, some people also become more vulnerable to infections.
Known Risk Factors
No single cause explains most cases of lymphoma, but several factors increase risk. Certain infections play a direct role: the Epstein-Barr virus (the same virus that causes mono) is linked to specific subtypes like Burkitt lymphoma and some T-cell lymphomas. Autoimmune diseases, where the immune system is chronically activated, are associated with a higher risk of non-Hodgkin lymphoma in particular.
Family history matters too. Having a close relative with lymphoma or another blood cancer increases your susceptibility, and a family history of autoimmune disease may compound that risk. On the environmental side, occupational exposure to benzene (found in petroleum refining, fuel distribution, and some industrial solvents) has emerged as a likely contributor. Polychlorinated biphenyls (PCBs), dioxins, and organochlorine pesticides have also been implicated, with some of the strongest evidence coming from long-term studies of workers and communities with measurable chemical exposure. Chlorinated solvents remain under investigation as well. That said, no single environmental chemical has been definitively established as a universal cause.
How Lymphoma Is Diagnosed
If your doctor suspects lymphoma based on symptoms and a physical exam, the gold standard for confirming it is an open lymph node biopsy, where a surgeon removes an entire lymph node or a large piece of one. This matters because the diagnosis depends on examining the full structure of the tissue. A fine-needle aspiration or core needle biopsy, which takes only a small sample, typically doesn’t provide enough tissue to identify Reed-Sternberg cells or to run the specialized tests needed to classify the subtype accurately.
Once lymphoma is confirmed, the next step is staging, which determines how far the disease has spread. This is done primarily with PET-CT scanning, a combination imaging technique that highlights areas of active cancer throughout the body. Staging runs from Stage I (cancer in a single group of lymph nodes) through Stage IV (cancer that has spread to organs outside the lymphatic system, such as the liver or bone marrow). The stage at diagnosis, combined with the specific subtype, shapes the entire treatment plan.
Treatment Options
Treatment varies dramatically depending on the type, subtype, and stage. Some slow-growing lymphomas don’t need immediate treatment at all. Instead, doctors may recommend active surveillance, sometimes called “watchful waiting,” where you’re monitored with regular check-ups and scans until the disease shows signs of progressing. This approach can spare you years of unnecessary side effects.
When treatment is needed, the backbone for most lymphomas is chemotherapy, often combined with immunotherapy drugs that help the immune system target cancer cells more precisely. Radiation therapy may be used alone for very early-stage disease or alongside chemotherapy for more advanced cases. For Hodgkin lymphoma, cure rates with standard treatment are high, and many patients achieve long-term remission.
For lymphomas that don’t respond to initial treatment or that come back, more advanced options exist. One of the most notable is CAR-T cell therapy, a form of immunotherapy where your own immune cells are collected, genetically reprogrammed in a lab to recognize and attack lymphoma cells, and then infused back into your body. This treatment is approved for several types of B-cell lymphoma, including diffuse large B-cell lymphoma, follicular lymphoma, and mantle cell lymphoma. It’s typically reserved for cancers that haven’t responded to other treatments or that relapse within 12 months of initial therapy. The process takes several weeks from cell collection to infusion, and patients sometimes receive chemotherapy or radiation as “bridging therapy” to keep the cancer in check while waiting for their modified cells to be ready.
Living With Lymphoma
Because lymphoma disrupts the very cells responsible for fighting infection, your immune system is compromised both by the disease itself and by many of its treatments. This means infections can be more frequent and more serious during and after therapy. Fatigue is one of the most persistent challenges patients report, sometimes lasting months after treatment ends.
For aggressive subtypes, the goal of treatment is a complete cure, and many patients achieve it. For indolent subtypes, the reality is often different. Slow-growing lymphomas may respond well to treatment but return years later, turning the disease into something managed over a long period rather than cured outright. Each relapse can be treated, and many people live for decades with indolent lymphoma, but the pattern of remission and recurrence requires ongoing monitoring and periodic retreatment.