The localization of lymphocytes, a specific type of WBCs (or white blood cells), in one or more lymph nodes is what is referred to as lymphoma – a cancer. In both the lymphatic and blood circulatory systems, lymphocytes travel all over the body. Tissue fluids are drained and carried all over the body as lymph and then back to the blood circulatory system via the lymphatic system, which is a network of lymph nodes and vessels (or lymphatics). In areas such as the groin, neck, chest, armpits, and abdomen, lymph nodes are found in chains or individually. As the lymph fluid goes through the nodes (tiny lymphoid tissue organs whose job it is to filter lymph), abnormal cells and microorganisms are destroyed. Natural killer cells, T-lymphocytes and B-lymphocytes are some of the lymphocytes and macrophages contained in lymph nodes.
The immune system is controlled by T-lymphocytes. When it comes to immune responses, these lymphocytes decide when a response is necessary, its scale or severity, in addition to triggering it. Furthermore, they counteract a variety of foreign bodies attacking the body. B-lymphocytes work to create antibodies that are activated when an individual gets a vaccine against hepatitis, mumps or measles, or any other diseases. 10 to 15 percent of all the lymphocytes in the bloodstream are of the natural killer (or NK) variety, another type of lymphocytes. Abnormal cells that have been attacked by viruses and cancerous cells are usually attacked and killed by NK cells.
In the case of lymphoma, any of these cells may be involved either singly or as a combination. The occurrence of abnormal cells in the lymph nodes, one or more, or lymphoid tissues could signal the onset of lymphoma. The uncontrollable reproduction of these cells means that their number exceeds that of normal cells in the affected node causing the node to grow in size before the abnormal cells start spreading to other nodes in the lymphatic system. The abnormal cells may also travel to the tonsils, thymus, bone marrow, adenoids and spleen, and other organs closely related to the lymphatic system.
T-cell lymphomas are less common than B-cell lymphomas.
Symptoms of Lymphoma
The lymph nodes in the groin, neck, and armpits may swell painlessly and/or the spleen becomes enlarged in people with lymphoma. Increased levels of abnormal lymphocytes may also be discovered in the blood of affected individuals. Additional signs and symptoms of lymphoma include:
- Episodes of chills and fever
- Instances of night sweats
- Significant loss of weight, up to 10 percent or higher, for no apparent reason
- Diminished appetite
- Pain in the neck or flank
The individual’s breathing may be affected if the lymph node in question is located in the chest area. If the affected lymph node is in the abdomen, abdominal pain may be experienced. Since the above symptoms may be mild in nature, diagnosing lymphoma may, at times, be quite hard. While some people may experience a low-grade fever, others may not have any noticeable signs. The physician, or individual suffering from lymphoma, may not be able to feel or see the swollen lymph node even though it is there.
The presence of Reed-Sternberg cells, big unique cells, characterizes Hodgkin disease/lymphoma.
People between the ages of twenty and forty years, as well as those over the age of 55, have a higher prevalence of Hodgkin lymphoma. Each year, around 9,000 individuals in the US are diagnosed with this disease, with 1,300 deaths, according to the ACS (or American Cancer Society).
A variety of theories have attempted to explain the cause of Hodgkin Lymphoma. The involvement of a virus, or other infectious agent, has been mentioned in a number of them. According to other theories, cell mutations are to blame. Specific causes are yet to be identified, even though research is still ongoing. Similarly, there has been no clear explanation as to why males appear to be more vulnerable to HL.
Based on the cells that are present as well as the abnormal lymph node structure, Hodgkin Lymphoma can be further divided. A depletion of lymphocytes, a higher number of small lymphocytes, or a combination of various types of cells or fibrosis (occurrence of bands of scarring) may be seen in lymph nodes. With HL, a benign, mostly mixed, reactive cell population forms the majority of the cells in the lymph nodes, while Reed-Sternberg cells (tumor cells) are the minority.
About 4 percent of all newly diagnosed cancer cases in the US are Non-Hodgkin lymphoma. This lymphoma is slightly more common in Caucasians and men than in women. Individuals with a compromised immune system, those with HIV/AIDS, as well as those at an advanced age, face a higher risk of developing this disease.
While around 20,000 people die from the disease annually, around 72,000 are diagnosed in a similar period according to the American Cancer Society. Since the 1970s, the occurrence of the disease is almost double. While cases relating to women account for the highest increase, the main reason for the upward trend is yet to be discovered. Since the late nineties, however, non-Hodgkin lymphoma related deaths have been on the decrease.
The systems used to classify the many different types of non-Hodgkin lymphoma have evolved as understanding about them grows. Some of the changes in the classification systems used are attributed to the introduction of new methods of evaluating the cells involved in the disease.
Many doctors have adopted the REAL (or Revised European American Lymphoma) classification proposed by the International Lymphoma Study Group back in the nineties. The main function that the cell should be providing was the main focus of this classification. For instance, while cell to cell interactions are left to T-lymphocytes, the main function of B-lymphocytes is to produce antibodies. These characteristics are combined with genetic and phenotypic studies of the cells under the WHO (or World Health Organization) classification system – which is also the latest system. Having been adopted by many healthcare professionals as the current standard, the World Health Organization classification added to the REAL classification.
Non-Hodgkin Lymphoma Types
Due to the various classification systems and changes made to them over the years, non-Hodgkin lymphoma classification can be somewhat confusing. Natural Killer and T- cell lymphomas are less common in the US than B-cell non-Hodgkin lymphomas. Around 15 percent of non-Hodgkin lymphomas affect T-lymphocytes, with approximately 85 percent involving mature B-lymphocytes.
The following are some of the most common B-cell lymphomas types:
* DLBCL (or Diffuse Large B-cell Lymphoma). Of all non-Hodgkin lymphoma cases in the US, DLBCL constitutes about a third. While this disease mostly occurs in older individuals, it can affect anyone and is considered to grow swiftly.
* Follicular Lymphoma. About a fifth of all lymphoma cases in the US are of this type. Over time, about a third of all Follicular lymphomas turn into the fast-growing DLBCL type described above, even though they are generally known to grow slower.
* B-cell chronic lymphocytic lymphoma / small lymphocytic lymphoma (or CLL/ SLL).
Characterized by small lymphoma cells, CLL/SLL is a slowly progressing disease. The lymphoma cells are mostly small-sized. While SLL generally involves the lymph nodes, CLL is predominantly found in the bone marrow; however, both of these are considered the same disease and combined make up about 24 percent of all lymphomas.
The following are some of the main types of T-cell lymphomas:
* Precursor T-lymphoblastic lymphoma (leukemia). Depending on where the affected cells are located, in the bone marrow or the blood, this disease can be considered to be leukemia or lymphoma. Of all lymphoma cases, about 1 percent fall under this category.
* Peripheral or Mature T-cell lymphomas. 4 to 5 percent of all lymphomas fall under the different known categories of mature T-cell lymphomas.
* Sezary Syndrome, Mycosis Fungoides, and Other Types Of Cutaneous T-Cell Lymphomas. These types of lymphomas are different from other types because, unlike the rest, they start on the skin instead of internal organs or lymphoid tissue. This means that even though they are quite uncommon, they very unique. Of all non-melanoma skin cancer cases, this specific group makes up less than 1 percent. Five percent of all lymphomas are skin lymphomas.
When it comes to testing, the main goal is to distinguish the condition from other conditions and recognize and keep track of complications, if any, in addition to diagnosing and staging the lymphoma. To diagnose lymphoma a few blood tests can be used.
The examination of affected lymphoid tissue and lymph nodes by a pathology specialist is the gold standard when it comes to testing for both non-Hodgkin and Hodgkin lymphomas. Using a fine needle aspiration procedure or biopsy obtained from the affected lymph tissue or node, the sample is evaluated microscopically.
The following lab tests may also be used:
* CBC (or Complete Blood Count). To rule out leukemia and other non-lymphoma conditions and to test for the presence of anemia, a CBC may be administered. The CBC can identify low platelet or low white blood cell counts that may indicate whether lymphoma is present in the blood and/or bone marrow
* Biopsy and Evaluation of The Bone Marrow. The cells in the bone marrow are examined using this test. Lymphoid aggregates and/or abnormal lymphoid cells may be found with lymphoma.
* Blood Smear Test. The quality of platelets, white and red blood cells, and that of lymphoma cells, or any other abnormal cells, where present, is examined under this test.
* Immunophenotyping. By testing for specific identifying markers inside or on the membrane of cells, this test can be used to spot affected cells. Usually listed numerically, these commonly used identifying factors are referred to as CD (or clusters of differentiation). Classification of the cells is possible by creating a list of the clusters of differentiation present on the cells. Immunohistochemistry and flow cytometry are a couple of the ways in which this test can be conducted.
* Chromosome Analysis Test. To establish whether bits of chromosomes have moved, chromosome analysis evaluates the chromosomes in the cancer cell nucleus. For lymphomas, this test is rarely used.
* Molecular Genetic Analysis Tests. To establish whether the cells under consideration belong to one clone, molecular genetic analysis can be used to look for genetic changes by examining the DNA of the cancerous cell.
* Body fluids, including cerebrospinal fluid, can be analyzed if the lymphoma is thought to have spread to other parts of the body.
* Beta-2 Microglobulin Test. The prognosis may be predicted with the help of the Beta-2 Microglobulin test.
* Serum Creatinine Test. If a disease referred to as nephritic syndrome, affecting the kidneys, is linked with Hodgkin lymphoma, serum creatinine levels may be higher than normal.
* Studies of Serum Chemistry. The prognosis may also be determined with the help of serum chemistry studies such as LDH (or lactate dehydrogenase).
* Hepatitis B Test. * Since rituximab therapy is linked with negative side effects in individuals suffering from hepatitis B, a hepatitis B test is used to determine the suitability of the treatment.
* HIV (Human Immunodeficiency Virus) Test. The lymphoma outcome in HIV patients may be improved by using an antiretroviral treatment.
The following non-laboratory tests may be used primarily to help stage and monitor lymphoma:
* MRI (or magnetic resonance imaging).
* Exploratory surgery (only necessary on occasion).
* Physical examination.
* CT (or computed tomography) scans.
* PET (or positron emission tomography) scans.
* Chest X-ray.