Lymphoma is a cancer, a pathological modification of the cells known as lymphocytes. They are members of the family of the white blood cells. It isn't very easy for the doctors to put the diagnosis and to make a classification of lymphomas. this aspect is very confusing for the patients too. It is essential to understand the development of normal lymphocytes and lymphoma.

The role of lymphocytes as of the hole white blood cells family is to help fight infection.There are two kinds of lymphocytes: B lymphocytes (B cells) and T lymphocytes (T cells). When there is a threat or an infection that attack the body B cells transforms into another kind of cells called plasma cells. This new formed cells, the plasma cells, secrete antibodies which are proteins that attach to the harmful or infectious particles. This particles that attack the human body and release the infection are known as "antigens". After the antibodies are attached to antigens, they are recognized by other white blood cells. These cells will attack and destroy the particles that injured the body.

T cells are involved in the immune response and they also can attack foreign particles. By binding directly to the antigens of viruses and tumor cells, T cells can eliminate them. The difference between T cells and B cells is that T cells do not secrete antibodies.

T and B cells are very numerous and they circulate throughout the body passing through lymph nodes and the spleen. During this circulation they look for "foreign" antigens to which they can react. The antigen stimulate the lymphocytes and they divide rapidly into other cells. If the stimulated cells leads to B cells, they also turn into plasma cells which begin secreting antibodies.

After the antigen is recognized, can react many different B cells and T cells which can recognize different pieces of the antigen. This causes the proliferation of the B cells and T cells. The result is many large groups of T and B lymphocytes. An exaggerated number of lymphocytes can cause lymph nodes, a congregation of lymphocytes, to enlarge. This is a clinical sign of the presence of an infection.

A lymphoma is a malignant form of lymphocytes. A lymphoma cell population is composed of identical lymphocytes. They have the same origin, a single T cell or a B cell.The abnormal process is that these cells may divide slowly without being distroyed, or divide rapidly. In both situations the result is an accumulation of a large number of lymphocytes which are identical. This exaggerate accumulation will cause lymph nodes to enlarge. Normal lymphocytes present different stages of maturation. Lymphoma cells do not mature, their development stop as it was frozen at one stage of development. Another cause of the presence of the lymphomas are specific genetic mutations

To make a correct classification of the lymphomas we have to take in consideration different aspects like the characteristics of the tumor cells, appearance or the morphology, type, genetic make-up or "genotype" and the clinical symptoms of the patient. The morphology of the malignant lymphocytes is established regarding the way the cells and tissues appear under a microscope. "Phenotype" or the type of the malignant cells is the term used to mention the different unique "markers" that can be found on the surface of the cells. Using special tests these markers can be determined in laboratories. The "genotype," means the DNA of the malignant lymphocytes. At this level, specialists discovered that often can exist specific genetic mutations. Even if the diagnosis of lymphoma is sure, it is not very easy to make theclasification. Classification tests may take weeks. They are very important and they mustn't be skiped because the therapy and prognosis are often closely related to the results of these tests.

There are two major groups of lymphomas: the Hodgkin and the Non- Hodgkin's disease.

In Hodgkin's disease appears unique malignant cells known as Reed-Sternberg cells. They are thought to be B cells. There are also other inflammatory cells. More common is the Non-Hodgkin's Lymphoma and the most alarming aspect is that it tends to affect young adults. The way it manifests and the treatment recommended are different than in other forms of lymphoma. There is also a good aspect of this disease because it is considered curable in most of the cases.