Non-Hodgkin lymphoma

Non-Hodgkin lymphoma (NHL) is a type of blood cancer that starts in lymphocytes, the white blood cells that are part of your body’s immune system.

Overview

Non-Hodgkin lymphoma, or NHL, encompasses different types of lymphoma that all share some specific characteristics.

Non-Hodgkin lymphoma is separate from the other main type of lymphoma, Hodgkin lymphoma, which is treated differently. NHL most often affects adults, and usually starts in lymph nodes or other lymph tissue but can start in the skin.

We know that NHL is linked with a number of risk factors, but we are still researching the cause of most lymphomas.

Genetic causes

We do have a better understanding now how certain changes in DNA can cause normal lymphocytes to become lymphoma cells. Oncogenes are genes that help cells grow, divide, and stay alive—tumor suppressor genes help keep cell division under control, or make cells die at the right time. We know that some lymphoma cancers are caused by DNA mutations that turn on oncogenes or turn off tumor suppressor genes. A family history of lymphoma does seem to increase the risk of lymphoma.

However, we now know that gene changes related to NHL are usually acquired during life rather than being inherited. This can happen from exposure to risk factors, but these changes can also occur for no apparent reason and seem to happen more often as we age.

Father and Son

There are three major groups of non-Hodgkin lymphoma as determined by the type of cell the lymphoma started in:

  • B-cell lymphoma. Occurs in about 90% of cases in western countries.
  • T-cell lymphoma. Occurs in about 10% of cases in western countries.
  • NK-cell lymphoma. Occurs in less than 1% of cases.

In addition to the three main types, we can also classify NHL by how quickly the cancer is growing, either indolent or aggressive.

Indolent and aggressive non-Hodgkin lymphomas are equally common in adults; in children, aggressive NHL is more common.

  • Indolent NHL. These types grow slowly, so you may not need to start treatment when first diagnosed.
  • Aggressive NHL. These types may develop rapidly, so we usually start treatment right away.

Some subtypes of lymphoma cannot easily be classified as indolent or aggressive.

Subtypes of B-cell lymphoma

  • Diffuse large B-cell lymphoma (DLBCL). The most common form.
  • Follicular lymphoma. The second-most common form.
  • Mantle cell lymphoma. Only 5% to 7% of people with NHL have mantle cell lymphoma.
  • Small lymphocytic lymphoma.
  • Double hit lymphoma. A highly aggressive subtype of DLBCL, accounting for about 5% of cases.
  • Primary mediastinal large B-cell lymphoma. An aggressive form of DLBCL, appearing as a large mass in the chest area.
  • Splenic marginal zone B-cell lymphoma. Begins in the spleen and usually involves the bone marrow and the blood.
  • Extranodal marginal zone B-cell lymphoma of MALT. Most commonly occurs in the stomach. Patients may have a history of autoimmune disease such as lupus, rheumatoid arthritis, or Sjögren syndrome. When MALT occurs in the stomach, it is may be caused by the bacteria Helicobacter pylori—antibiotics can effectively treat this.
  • Nodal marginal zone B-cell lymphoma. A rare type of indolent lymphoma involves the lymph nodes.
  • Lymphoplasmacytic lymphoma. A rare type of indolent form of lymphoma, often involving the bone marrow, and sometimes the lymph nodes and spleen. This type can result in a condition called Waldenstrom’s macroglobulinemia (WM).
  • Primary effusion lymphoma. A rare and very aggressive form.
  • Burkitt lymphoma or Burkitt cell leukemia. A very rare and aggressive type, with three forms: endemic, sporadic and Iimmunodeficiency-related lymphoma. Burkitt lymphoma is often curable.

Subtypes of T-cell and NK-cell lymphoma

  • Anaplastic large cell lymphoma, primary cutaneous type. Involves only the skin.
  • Anaplastic large cell lymphoma, systemic type. Makes up about 2% of all lymphomas and about 10% of all childhood lymphomas.
  • Peripheral T-cell lymphoma, not otherwise specified (NOS). An aggressive form that is often advanced when diagnosed.
  • Angioimmunoblastic T-cell lymphoma. An aggressive form.
  • Adult T-cell lymphoma/leukemia (human T-cell lymphotropic virus type I positive). An aggressive type that often involves the bone and skin.
  • Extranodal NK/T-cell lymphoma, nasal type. An aggressive type, very rare in the United States.
  • Enteropathy-associated T-cell lymphoma. Rare in the United States but more common in Europe.
  • Gamma/delta hepatosplenic T-cell lymphoma. An aggressive form of peripheral T-cell lymphoma that involves the liver and spleen.
  • Subcutaneous panniculitis-like T-cell lymphoma. A form of peripheral T-cell lymphoma, similar to gamma/delta hepatosplenic T-cell lymphoma.
  • Mycosis fungoides. A rare T-cell lymphoma that primarily involves the skin.