Adult non-Hodgkin’s lymphoma is a disease in which malignant (cancer) cells form in the lymph system.

The lymph system is part of the immune system and is made up of the following:

• Lymph: Colorless, watery fluid that travels through the lymph system and carries white blood cells called lymphocytes. Lymphocytes protect the body against infections and the growth of tumors.
• Lymph vessels: A network of thin tubes that collect lymph from different parts of the body and return it to the bloodstream.
• Lymph nodes: Small, bean-shaped structures that filter substances in lymph and help fight infection and disease. Lymph nodes are located along the network of lymph vessels found throughout the body. Clusters of lymph nodes are found in the underarm, pelvis, neck, abdomen, and groin.
• Spleen: An organ that produces lymphocytes, filters the blood, stores blood cells, and destroys old blood cells. It is located on the left side of the abdomen near the stomach.
• Thymus: An organ in which lymphocytes grow and multiply. The thymus is in the chest behind the breastbone.
• Tonsils: Two small masses of lymph tissue at the back of the throat. The tonsils produce lymphocytes.
• Bone marrow: The soft, spongy tissue in the center of large bones. Bone marrow produces white blood cells, red blood cells, and platelets.

Because lymph tissue is found throughout the body, adult non-Hodgkin’s lymphoma can begin in almost any part of the body. Cancer can spread to the liver and many other organs and tissues.

There are many different types of lymphoma.

Lymphomas are divided into two general types: Hodgkin’s lymphoma and non-Hodgkin’s lymphoma.

Risk factors for adult non-Hodgkin’s lymphoma include the following:

• Being older, male, or white.
• Having one of the following medical conditions:

1. An inherited immune disorder (for example, hypogammaglobulinemia or Wiskott-Aldrich syndrome).
2. An autoimmune disease (for example, rheumatoid arthritis, psoriasis, or Sjögren's syndrome).
3. HIV/AIDS.
4. Human T-lymphotrophic virus type I or Epstein-Barr virus.
5. A history of Helicobacter pylori infection.

• Taking immunosuppressant drugs after an organ transplant.
• Being exposed to certain pesticides.
• A diet high in meats and fat.
• Past treatment for Hodgkin’s lymphoma.

Possible signs of adult non-Hodgkin’s lymphoma include fever, sweating, fatigue, and weight loss.

These and other symptoms may be caused by adult non-Hodgkin’s lymphoma. Other conditions may cause the same symptoms. A doctor should be consulted if any of the following problems occur:

• Painless swelling in the lymph nodes in the neck, underarm, groin, or stomach.
• Fever for no known reason.
• Drenching night sweats.
• Feeling very tired.
• Weight loss for no known reason.
• Skin rash or itchy skin.
• Pain in the chest, abdomen, or bones for no known reason.

Tests that examine the body and lymph system are used to help detect (find) and diagnose adult non-Hodgkin’s lymphoma.

The following tests and procedures may be used:

• Physical exam and history: An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient’s health habits and past illnesses and treatments will also be taken.
• Complete blood count (CBC): A procedure in which a sample of blood is drawn and checked for the following:

1. The number of red blood cells, white blood cells, and platelets.
2. The amount of hemoglobin (the protein that carries oxygen) in the red blood cells.
3. The portion of the sample made up of red blood cells.

• Blood chemistry studies: A procedure in which a blood sample is checked to measure the amounts of certain substances released into the blood by organs and tissues in the body. An unusual (higher or lower than normal) amount of a substance can be a sign of disease in the organ or tissue that produces it.
• Lymph node biopsy: The removal of all or part of a lymph node. A pathologist views the tissue under a microscope to look for cancer cells. One of the following types of biopsies may be done:

1. Excisional biopsy: The removal of an entire lymph node.
2. Incisional biopsy: The removal of part of a lymph node.
3. Core biopsy: The removal of part of a lymph node using a wide needle.
4. Needle biopsy: The removal of part of a lymph node using a thin needle. This procedure is also called a fine-needle aspiration biopsy.
5. Bone marrow aspiration and biopsy: The removal of a small piece of bone and bone marrow by inserting a needle into the hipbone or breastbone. A pathologist views both the bone and bone marrow samples under a microscope to look for signs of cancer.

• Liver function tests: A procedure in which a blood sample is checked to measure the amounts of certain substances released into the blood by the liver. For non-Hodgkin's lymphoma, the blood is checked for an enzyme called lactate dehydrogenase (LDH). LDH levels help determine prognosis (chance of recovery).

Certain factors affect prognosis (chance of recovery) and treatment options.

The prognosis (chance of recovery) and treatment options depend on the following:

• The stage of the cancer.
• The type of non-Hodgkin's lymphoma.
• The patient’s age and general health.
• Whether the lymphoma has just been diagnosed or has recurred (come back).
• Prognosis also depends on the level of LDH in the blood.