Your doctor will perform a thorough diagnostic screening to determine what type of non-Hodgkin lymphoma you have and its stage. Diagnostic testing can include:

  • Physical exam.
  • Biopsies of enlarged lymph nodes or other abnormal areas.
  • Blood tests.
  • Imaging tests, such as a PET scan and CT scan.
  • Bone marrow aspiration and biopsy.
  • Lumbar puncture (spinal tap).

UCHealth follows the World Health Organization (WHO) classification system for the many types of non-Hodgkin lymphoma. Treatment for NHL depends on the type, so it’s critical that we determine the exact type of lymphoma you have.

The WHO system groups lymphomas based on:

  • The type of lymphocyte the lymphoma starts in (see below).
  • How the lymphoma looks under a microscope.
  • The chromosome features of the lymphoma cells.
  • The presence of certain proteins on the surface of the cancer cells.

Lymphocyte types: B-cell v. T-cell

Your lymph system is made up mainly of lymphocytes, a type of white blood cell that helps the body fight infections. The first criteria for WHO classification is the type of lymphocyte involved. There are two main types of lymphocytes:

  • B lymphocytes (B cells). B cells normally help protect the body against bacteria and viruses by making proteins called antibodies. The antibodies attach to the germs, marking them for destruction by other parts of the immune system.
  • T lymphocytes (T cells). There are several types. Some T cells destroy germs or abnormal cells in the body, while other T cells help boost or slow the activity of other immune system cells.

NHL types grouped by speed of growth and spread

  • Indolent lymphomas grow and spread slowly Some indolent lymphomas might not need to be treated right away, but can be watched closely instead. The most common type of indolent lymphoma in the United States is follicular lymphoma.
  • Aggressive lymphomas grow and spread quickly, and usually need to be treated right away. The most common type of aggressive lymphoma in the United States is diffuse large B cell lymphoma (DLBCL).

Some types of lymphoma, like mantle cell lymphoma, don’t fit neatly into either of these categories.

Regardless of how quickly they grow, all non-Hodgkin lymphomas can spread to other parts of the lymph system if not treated. Eventually, they can also spread to other parts of the body, such as the liver, brain, or bone marrow.


UCHealth follows the Lugano classification for staging NHL in adults, which uses Roman numerals I through IV (1-4). Limited stage (I or II) lymphomas that affect an organ outside the lymph system have an E added.

Stage I

The lymphoma is in only one lymph node area or lymphoid organ such as the tonsils (I).
The cancer is found only in one area of a single organ outside of the lymph system (IE).

Stage II

The lymphoma is in two or more groups of lymph nodes on the same side of (above or below) the diaphragm (the thin band of muscle that separates the chest and abdomen). For example, this might include nodes in the underarm and neck area (II) but not the combination of underarm and groin nodes (III).
The lymphoma is in a group of lymph nodes) and in one area of a nearby organ (IIE). It may also affect other groups of lymph nodes on the same side of the diaphragm.

Stage III

The lymphoma is in lymph node areas on both sides of (above and below) the diaphragm.
The lymphoma is in lymph nodes above the diaphragm, as well as in the spleen.

Stage IV

The lymphoma has spread widely into at least one organ outside the lymph system, such as the bone marrow, liver, or lung.

Non-Hodgkin lymphoma: learn more