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Lymphomas- causes, pathophysiology, sign and symptoms, diagnostic tests

LYMPHOMA CAUSES/RISK FACTORS

The exact causes of lymphoma are not known. Several factors have been linked to an increased risk of developing lymphoma, but it is unclear what role they play in the actual development of lymphoma. These risk factors include the following:

  1. Age: Generally, the risk of NHL increases with advancing age. HL in the elderly is associated with a poorer prognosis than that observed in younger patients. In the 20-24-year age group, the incidence of lymphoma is 2.4 cases per 100,000 while it increases to 46 cases per 100,000 in the 60-64-year-old age group.
  2. Infections
    • Infection with HIV
    • Infection with Epstein-Barr virus (EBV), one of the etiologic factors in mononucleosis
    • Infection with Helicobacter pylori, a bacterium that lives in the digestive tract
    • Infection with hepatitis B or hepatitis C virus
  3. Medical conditions that compromise the immune system
    • HIV
    • Autoimmune disease
    • Use of immune suppressive therapy (often used following organ transplant)
    • Inherited immunodeficiency diseases (severe combined immunodeficiency, ataxia telangiectasia, among a host of others
  4. Exposure to toxic chemicals
    • Farm work or an occupation with exposure to certain toxic chemicals such as pesticides, herbicides, or benzene and/or other solvents
    • Hair dye use has been linked to higher rates of lymphoma especially in patients who started to use the dyes before 1980.
  5. Genetics: Family history of lymphoma

The presence of these risk factors does not mean a person will actually develop lymphoma. In fact, most people with one or several of these risk factors do not develop lymphomas.

 

PATHOPHYSIOLOGY

  1. As the abnormal cells multiply, they may collect in one or more lymph nodes or in other lymph tissues such as the spleen.
  2. As the cells continue to multiply, they form a mass often referred to as a tumor.
  3. Tumors often overwhelm surrounding tissues by invading their space, thereby depriving them of the necessary oxygen and nutrients needed to survive and function normally.
  4. In lymphoma, abnormal lymphocytes travel from one lymph node to the next, and sometimes to remote organs, via the lymphatic system.
  5. While lymphomas are often confined to lymph nodes and other lymphatic tissue, they can spread to other types of tissue almost anywhere in the body. Lymphoma development outside of lymphatic tissue is called extra-nodal disease.

LYMPHOMA SYMPTOMS AND SIGNS

Often, the first sign of lymphoma is a painless swelling in the neck, under an arm, or in the groin.

  1. Lymph nodes or tissues elsewhere in the body may also swell. The spleen, for example, often becomes enlarged in lymphoma.
  2. The enlarged lymph node sometimes causes other symptoms by pressing against a vein or lymphatic vessel (swelling of an arm or leg), a nerve (pain, numbness, or tingling), or the stomach (early feeling of fullness).
  3. Enlargement of the spleen may cause abdominal pain or discomfort
  4. Many people have no other symptoms.

Symptoms of lymphoma may include the following:

  1. Fevers
  2. Chills
  3. Unexplained weight loss
  4. Night sweats
  5. Lack of energy
  6. Itching (up to 25% of patients develop this itch, most commonly in the lower extremity but it can occur anywhere, be local, or spreading over the whole body.

These symptoms are nonspecific. This means that they could be caused by any number of conditions unrelated to cancer. For instance, they could be signs of the flu or other viral infection, but in those cases, they would not last very long. In lymphoma, the symptoms persist over time and cannot be explained by an infection or another disease.

LYMPHOMA DIAGNOSIS

History taking and Physical examination

If a person has swelling or symptoms of Lymphomas, then the following history should be taken:

  • When they began
  • Recent illnesses
  • Past or current medical problems
  • Any medications
  • Workplace, health history, family history, and habits and lifestyle
  • Thorough examination

Blood tests

Blood is drawn for various tests:

  1. Evaluate the function and performance of blood cells and important organs, such as the liver and kidneys.
  2. Blood chemicals or enzymes (lactate dehydrogenase [LDH]) may be determined. High levels of LDH in cases in which NHL is suspected may indicate a more aggressive form of the disorder.
  3. Other tests may be done to learn more about lymphoma subtypes.

Biopsy

If there is a swelling (also called lump or mass), a sample of tissue from the swelling will be removed for examination or biopsy. Any of several methods can be used to obtain a biopsy of a mass.

  1. Core-needle biopsy: Masses that can be seen and felt under the skin are relatively easy to biopsy. A hollow needle can be inserted into the mass and a small sample removed with the needle. This is usually done in the OPD with a local anaesthetic.
  2. Surgical biopsy: This involves removal of the entire swollen lymph node through a small incision in the skin. This procedure often is done with a local anesthetic, but it sometimes requires a general anesthetic.
  3. Laparoscope biopsy: This means making a tiny incision in the skin and inserting a thin tube with a light and a camera on the end. The camera sends pictures of the inside of the body to a video monitor, and the surgeon can see the mass. A small cutting tool on the end of the laparoscope can remove all or part of the mass. This tissue is withdrawn from the body with the laparoscope.

Imaging studies

If there is no palpable mass in the presence of persistent symptoms, imaging studies will likely be carried out in order to determine whether a mass is present and, if so, how then to direct a biopsy.

  1. X-rays: In certain parts of the body, such as the chest, a simple X-ray can sometimes detect lymphoma.
  2. CT scan: This test provides a three-dimensional view and much greater detail and may detect enlarged lymph nodes and other masses anywhere in the body.
  3. MRI scan: MRI provides better definition than CT scan in certain parts of the body, especially the brain and the spinal cord.
  4. Lymphangiogram: This approach, which provides an image of the lymphatic system by tracing a dye that moves though the system, has essentially been replaced by CT scan or MRI.
  5. Gallium scan: Lymphomas tend to collect a substance called gallium when injected into the body. For this test, a tiny amount of radioactive gallium is injected into the body. A scan is then done to find areas where the gallium has collected. Collections of gallium suggest a tumor.
  6. Positron-emission tomographic (PET) scan: PET scan is a newer alternative to lymphangiogram and gallium scan for detecting areas in the body that are affected by lymphoma. A tiny amount of a radioactive substance is injected into the body and then traced on the PET scan. Sites of radioactivity on the scan indicate areas of increased metabolic activity, which implies the presence of a tumor.

Bone marrow examination

Most of the time, an examination of the bone marrow is necessary to see if the marrow is affected by the lymphoma. This is done by collecting a biopsy of the bone marrow.

  1. Samples are taken, usually from a hip bone.
  2. A pathologist examines the bone marrow under a microscope.
  3. Bone marrow containing certain types of abnormal B or T lymphocytes confirms lymphoma.
  4. Bone marrow biopsy can be an uncomfortable procedure, but it can usually be performed in a medical office. Most people receive pain medication prior to the procedure to make them more comfortable.

Other tests

  1. Lumbar puncture: Also known as spinal tap and is done if the lymphoma has affected the central nervous system, the cerebrospinal fluid will likely contain lymphoma cells.
  2. Organ function tests: These tests are usually done before starting treatment to make sure that one’s organs are healthy enough to withstand the side effects of therapy. Examples include an echocardiogram or MUGA scan (a test that provides a movie-like image of the working heart) for the heart and pulmonary function tests for the lungs.

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