Lymphoma: Types, Symptoms, Causes, Risk Factors and Diagnosis
Lymphoma also termed lymphatic cancer is a type of cancer that begins in infection-fighting cells of the immune system, called lymphocytes.
These cells are in the lymph nodes, spleen, thymus, bone marrow, and other parts of the body. Lymphoma represents many different cancers of lymphocyte, about 35 to 60 different sub types. When you have lymphoma, lymphocytes change and grow out of control. The lymphatic system is part of the immune system which consists of a network of vessels that carry a fluid called lymph.
Lymph contains white blood cells called lymphocytes that are also present in blood and tissues. In the precancerous stages of development lymphocytes attack a variety of infectious agents as well as many cells. Lymph nodes are small collections of lymph tissue that occur throughout the body. Lymph nodes that are scattered throughout the body are connected by lymphatic channels. Lymph flows through the lymph nodes, as well as through other lymphatic tissues including the spleen, the tonsils, the bone marrow, and the thymus gland. These lymph nodes filter the lymph, which may carry bacteria, viruses, or other microbes. At infection sites, large numbers of these microbial organisms collect in the regional lymph nodes and produce the local swelling and tenderness.These collections of lymph nodes are called swollen glands.
Lymphocytes recognize infectious organisms and abnormal cells and destroy them. There are two major sub types of lymphocytes called as B lymphocytes and T lymphocytes, also referred to as B cells and T cells. B lymphocytes produce antibodies. Antibodies are the proteins that circulate through the blood and lymph and attach to infectious organisms and abnormal cells. Antibodies essentially alert other cells of the immune system to recognize and destroy the infectious organisms and abnormal cells, also known as pathogens. The process is known as humoral immunity.
T cells, when activated, can kill pathogens directly. T cells also play a part in the mechanisms of immune system control to prevent the system from inappropriate overactivity or underactivity. The B and T lymphocytes are capable of remembering the pathogens and will fight it off if it returns.
When normal cells grow and multiply uncontrollably, cancer occurs. Lymphoma is a malignant transformation of either B or T cells or their sub types. As the abnormal cells multiply, they may collect in one or more lymph nodes or in other lymph tissues such as the spleen. They form a mass often referred to as a tumor when continue to multiply. Often tumors spread over surrounding tissues by invading their space, thereby depriving them of the necessary oxygen and nutrients needed to survive and function normally.
Abnormal lymphocytes travel from one lymph node to the next in lymphoma. Sometimes it travel to remote organs, via the lymphatic system. Lymphomas can spread to other types of tissue almost anywhere in the body. When lymphoma develops outside of lymphatic tissue that is called extranodal disease.
There are two main types of lymphoma:
Both of these may be associated with the same symptoms, and often have similar appearance on physical examination such as swollen lymph nodes. However, because of their distinct appearance under the microscope and their cell surface markers, they are distinguishable via microscopic examination of a tissue biopsy sample.
Non-Hodgkin and Hodgkin lymphoma involve different types of lymphocyte cells. Every type of lymphoma grows at a different rate and responds differently to treatment.
Hodgkin's disease develops from a specific abnormal B lymphocyte cell where as NHL may develop from either abnormal B or T cells. These are distinguished by unique genetic markers. Non-Hodgkin's lymphoma is more common than Hodgkin's lymphoma.
As many of the symptoms of lymphoma can also be warning signs of other illnesses, a proper diagnosis is always required to begin any treatment. The first sign of lymphoma is a painless swelling of lymph nodes in the neck, under an arm, or in the groin. Lymph nodes or tissues elsewhere in the body may also swell. For example enlarged spleen or Splenomegaly is one of the symptoms which indicates lymphoma. Splenomegaly may cause abdominal pain or discomfort.
The causes of splenomegaly vary widely and range from malignancy (cancers), infections, infiltration of the spleen from other diseases, inflammatory conditions, congestion and blood cell diseases.
Some of the most common causes of an enlarged spleen include the following:
Symptoms of lymphoma may vary from patient to patient and may include one or more the following:
The exact causes of lymphoma are unknown. Several factors are associated with an increased risk of developing lymphoma, but the role they play in the actual development of lymphoma is unclear. These risk factors include the following:
Generally, the risk of lymphoma increases with advancing age. If you are between 15 and 40 years or older than 55 you are at a risk of developing Hodgkin lymphoma and if you are at 60s or older for non-Hodgkin lymphoma.
Family history of lymphoma such as a close relative who had lymphoma.
The presence of these risk factors does not necessarily mean a person will actually develop lymphoma. But people with lymphoma usually have one or more of these risk factors.
If a person has swelling or any of the above symptoms, his or her health-care provider will ask many questions about the symptoms. These include, when they began, recent illnesses, past or current medical problems, any medications, workplace, health history, family history, and habits and lifestyle. These questions are followed by a thorough examination.
Initially your doctor will do a physical exam, including a check for swollen lymph nodes. Most of the time, an infection unrelated to cancer causes swollen lymph nodes.
After initial examination if it is suspected that patient may have lymphoma, he/she will undergo a series of tests for further clarification. Sometimes the patient might be referred to a hematologist/oncologist who has specialization in blood diseases and cancer.
These test are done to check the number of certain cells, levels of other substances, or evidence of infection in your blood and lymphoma subtypes. The function and performance of blood cells and important organs, such as the liver and kidneys can be evaluated.
Certain blood chemicals or enzymes such as lactate dehydrogenase (LDH) may be determined. High levels of LDH may indicate a more aggressive form of the disorder in cases in which NHL is suspected.
If there is presence of a swelling ,lump or mass, a sample of tissue from the swelling area will be removed for examination by a pathologist. This procedure is called a biopsy which can be done in several ways.
A pathologist is a physician who specializes in diagnosing diseases by looking at cells and tissues. After examining the tissue sample with a microscope, the pathologist will specify in his report whether the tissue is lymphoma and the type and subset of lymphoma.
Imaging studies will be done if there is no palpable mass and still you have symptoms of lymphoma. These can determine whether a mass is present and, if so, how then to direct a biopsy. Types of imaging test done to diagnose lymphoma include:
In certain parts of the body, such as the chest, a simple X-ray can sometimes detect lymphoma.
This test provides a three-dimensional view and much greater detail images. This may detect enlarged lymph nodes and other masses anywhere in the body.
MRI gives three-dimensional images similar to the CT scan with more detail images. MRI provides better clearance than CT scan in certain parts of the body, especially the brain and the spinal cord.
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 in turn is an indication of presence of a tumor.
To check if the marrow is affected by the lymphoma, an examination of the bone marrow is required in some cases. This is done by collecting a biopsy of the bone marrow.Tissue samples are taken, usually from the pelvis bone and a pathologist examines the bone marrow under a microscope. Bone marrow containing certain types of abnormal B or T lymphocytes confirms lymphoma. As bone marrow biopsy can be an uncomfortable procedure, pain medication prior to the procedure can be given to make the patient more comfortable. It is usually performed in a medical office.