There are two major types of lymphoma: Hodgkin lymphoma and non-Hodgkin lymphoma. The non-Hodgkin lymphoma is further subclassified according to the types of lymphocytes: B cells or T cells. Both types of lymphocytes are major players in our immune system.
B lymphocytes produce antibodies (proteins that circulate through the blood and lymph and attach to infectious organisms and abnormal cells called pathogens.) The presence of these antibodies alerts the immune system to recognize and destroy pathogens.
T cells can kill the pathogens directly and play a part in the mechanisms of immune system control to prevent the system from inappropriate activity.
Lymphoma is a malignant transformation that occurs in the DNA of either B or T lymphocytes or their subtypes that causes the cell to grow and divide uncontrollably into cancerous tumors.
Stages of non-Hodgkin’s lymphoma:
Stage I: Lymphoma is found only in a single lymph node, in the area immediately surrounding that node, or in a single organ.
Stage II: The lymphoma involves more than one lymph node area on one side of the diaphragm.
Stage III: The lymphoma involves lymph node regions above and below the diaphragm.
Stage IV: The lymphoma involves one or more organs outside the lymph system, or a single organ and a distant lymph node site.
Nodal or Extranodal: When the lymphoma is present primarily in the lymph nodes, it is called nodal disease. In some patients, the lymphoma may grow out of the lymph system into adjacent organs. This is referred to as extranodal extension and designated by an E following the stage.
There are more than 30 types of non-Hodgkin’s lymphoma that can be formed from either B cells or T cells. These types are divided into low-grade lymphoma, or high-grade lymphoma. Low-grade Lymphoma is not usually treated; high-grade lymphoma requires treatment.
B cell non-Hodgkin’s lymphomas include: Burkitt lymphoma, chronic lymphocytic leukemia (CLL,) small lymphocytic lymphom (SLL) diffuse large B cell lymphoma, follicular lymphoma, immunoblastic large cell lymhoma, precursor B-lymphoblastic lymphoma, and mantle cell lymphoma.
T-cell non-Hodgkin’s lymphomas include: mycosis fungoides, anaplastic large cell lymphoma, and precursor T-lymphoblastic lymphoma.
The non-Hodgkin’s lymphomas can be divided into prognostic groups:
Low-grade, sometimes called Indolent, NHL: these types of low-grade lymphoma grow very slowly. Watchful waiting is often the first step with lowgrade NHL, where the patient is followed closely, and treatment is started only when symptoms develop or the disease begins to change. Radiation therapy may eliminate the disease in localized low-grade lymphoma. Lowgrade non-Hodgkin’s lymphoma include:
Follicular lymphoma: the most common form of low-grade lymphoma. Over 90% have the CD20 protein on the surface of their cells, and most follicular lymphomas have the genetic abnormality that results in the production of a protein called bcl-2.
Marginal zone lymphomas: the three main types of marginal zone lymphoma are splenic marginal lymphoma, a rare lymphoma of the spleen, nodal marginal zone lymphoma, and MALT lymphomas, which arise in the mucosa linings of the stomach, lung, thyroid, salivary or tear glands.
Mantle cell lymphoma: characterized by the protein cyclin DI in the lymphoma cells. Mantle cell lymphoma can behave like a high grade lymphoma and spread aggressively to the bone marrow, blood, and spleen, and is often treated as high grade lymphoma.
Chronic lymphocytic leukemia: this low-grade lymphoma is also known as CLL, and is often diagnosed in patients with no symptoms but a high white blood cell count and enlarged lymph nodes. CLL starts in the white blood cells in the bone marrow and spreads to the blood, lymph nodes, liver, and spleen. CLL patients with cells that contain a low amount of the ZAP-70 and CD38 proteins tend to grow very slowly, those expressing high amount of these proteins grow more aggressively.
Lymphoplasmacytic lymphomas: belongs to a group of low-grade lymphomas in which malignant B cells fill up the bone marrow or enlarge the lymph nodes or spleen. Most lymphoplasmacytic lymphomas are called Waldenstrom’s macroglobulinemia, which is characterized by excess protein in the blood that can cause blurry vision and headaches.
High-grade non-Hodgkin’s lymphoma: these types of lymphoma may develop rapidly, and usually require intensive chemotherapy. Aggressive, or high-grade non-Hodgkin’s lymphoma include:
Diffuse large B-cell lymphoma: is the most common type of highgrade lymphoma. It is usually diagnosed with rapidly enlarging lymph nodes, but it can arise outside of the lymphatic system, in the gastrointestinal tract, testes, thyroid, skin, breast, bone, or brain.
Mediastinal large B-cell lymphoma: also called primary mediastinal large B-cell lymphoma, tends to occur in people in their 20s and 30s. Enlarged lymph nodes in the chest are usually found at diagnosis, which can cause shortness of breath.
Peripheral T-cell lymphoma: this type of lymphoma accounts for 7-8% of non-Hodgkin’s lymphoma cases, and is characterized by enlargement of lymph nodes, liver and spleen, and fever and weight loss.
Burkitt’s lymphoma: is a fast growing disease which usually requires immediate treatment. It appears first in the lymph nodes, and sometimes in the bowel.
Lymphoblastic lymphoma: is an uncommon type of high-grade non-Hodgkin’s lymphoma. It usually develops from T-cells. This lymphoma is usually occurs in people under the age of 35.
Anaplastic large-cell lymphoma: is a form of T-cell lymphoma which has a good prognosis with chemotherapy.
Enteropathy associated T-cell lymphoma: is a type of rare type of high-grade non-Hodgkin’s lymphoma that arises from T cells. It originates in the bowel, and often spreads to neighboring lymph nodes.
Hodgkin lymphoma: this type of lymphoma is commonly seen in younger age, with a peak at 20 and 40 year old. The presentation is usually as mediastinal mass. The diagnosis is confirmed on a tissue biopsy showing a characteristic large cells called Reed-Sternberg cells.