Classification Of Non Hodgkin Lymphoma Biology Essay

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Depending on the morphology, prognosis, genetic and clinical features Non-Hodgkin Lymphoma has a complex diversity. According to World Health Organization (WHO) NHL is classified based on not only the physical appearance of lymphoma cells under a microscope but also genetic features and the presence of specific proteins in the cells.

Some of the well-known NHLs are discussed below:

B-cell lymphomas

NHL can be a result of malignancies of either T-cell or B-cell lymphocytes. More common is B-cell lymphoma which can be of different types

Diffuse large B-cell lymphoma

Diffuse large B-cell lymphoma (DLBCL) occurs mainly at an older age. Generally, it begins with the painless swelling of an internal lymph node located in the chest, abdomen, armpit or neck. This grows very fast along with some other symptoms such as high temperatures, weight loss and night sweats. These are known as B symptoms.

Follicular lymphoma

Follicular lymphoma refers to the growth of the lymph nodes in a circular pattern. It can affect any lymph node as well as the bone marrow, resulting in a slow but non curable growth.

Chronic lymphocytic leukemia

Chronic lymphocytic leukemia is also a slow growing lymphoma which occurs mainly in blood or bone marrow.

Mantle cell lymphoma

Mantle cell lymphoma is more common in a late age and in men. Bone marrow, lymph nodes and spleen are the common sites of this type of lymphoma.

Marginal zone B-cell lymphomas

There are 3 main types of marginal zone lymphomas.

….Extranodal marginal zone B-cell lymphomas, also known as mucosa-associated lymphoid tissue (MALT) lymphomas which occur in extranodal areas such as stomach, lung, skin, thyroid, salivary glands and tissues surrounding the eye.

….Nodal marginal zone B-cell lymphoma

….Splenic marginal zone B-cell lymphoma

Primary mediastinal B-cell lymphoma

This lymphoma involves mediastinum and thus causes breathing problems. Swelling of face and arms can be resulted as a consequence of the blockade of superior vena cava.

Burkitt lymphoma

Burkitt lumphoma is caused by Epstein-Barr virus (or E-B virus) which genetically modifies the infected B-lymphocytes into cancer cells.

Lymphoplasmacytic lymphoma (Waldenstrom macroglobulinemia)

lymphoplasmacytic cells are B-cells which are developed in plasma cells. This lymphoma results from the production of abnormal lymphoplasmacytic cells by bone marrow. These abnormal cells produce large amounts of the protein immunoglobulin macroglobulin (IgM).

Hairy cell leukemia

This rare type of lymphoma is characterized with small B cell lymphocytes with hairy projections.

Primary central nervous system (CNS) lymphoma

This is generally found in patients with weak immune system such as AIDS patients. It can cause paralysis or even seizures.

T-cell lymphomas

Peripheral T-cell lymphomas

This lymphoma results when abnormal lymphocyte are mainly present in peripheral circulating blood.

Cutaneous T-cell lymphomas (mycosis fungoides, Sezary syndrome): This usually affects the skin.

Angioimmunoblastic T-cell lymphoma: this is a fast growing lymphoma occurring mainly in skin, lungs, liver, bone marrow and bones.

Extranodal natural killer/T-cell lymphoma, nasal type: This type of lymphoma can affect any age and often causes cancerous growth in the upper airway passages like nose and throat.

Enteropathy type T-cell lymphoma: This is a malignancy progression of a disease called gluten-sensitive enteropathy resulting of the invasion of intestinal wall.

Subcutaneous panniculitis-like T-cell lymphoma: This type of lymphoma causes a circular growth of the deep layer of skin.

Anaplastic large cell lymphoma: It occurs usually at a young age causing cancers of the skin.

Risk factors of NHL:

Age and gender

Old age is one of the strongest risk factor of NHL. Men are generally higher at risk than women for certain types of NHL for some unknown reasons.

Geographical and ethnic origin

As a general, developed countries have the higher rates of NHL. Some specific types are more related to certain regions of the world.

Exposure to certain chemicals and radiation

Benzene and certain herbicides and insecticides may increase the possibility of the onset of NHL. Patients taking certain chemotherapy drugs are at higher risk of developing the disease.

Nuclear reaction exposure and radiotherapy used for certain types of disease can play a role as risk for the disease.

Immune system deficiency

Severe combined immunodeficiency disease [SCID], Wiskott-Aldrich syndrome), acquired immunodeficiency states (eg, AIDS), and induced immunodeficiency states (eg, immunosuppression) are considered as risk factors for NHL.

Autoimmune diseases

Patients suffering from chronic autoimmune diseases such as Sjögren syndrome and Hashimoto thyroiditis, rheumatoid arthritis, systemic lupus erythematosus (SLE, or lupus) are more likely to develop the disease later on.

Certain infections

Several types of infections may raise the risk of non-Hodgkin lymphoma in different ways.

Infections that directly transform lymphocytes

Ceratin viruses like human T-cell leukemia/lymphoma virus (HTLV-1) and the Epstein-Barr virus (EBV) can cause genetic alteration to transform the lymphocytes to develop malignancy.

Infections that weaken the immune system

Aids virus develops immune system deficiency which can lead to some specific type of NHL like Burkitt lymphoma and diffuse large B-cell lymphoma.

Infections that cause chronic immune stimulation

Mucosa-associated lymphoid tissue (MALT) lymphoma of the stomach is often related to long- term Helicobacter pylori induced infection.

Body weight and diet

Obesity and low intake of fruits and vegetables are also considered as risk factors of NHL.

Signs and symptoms of non-Hodgkin lymphoma

More common signs and symptoms of NHL are listed below:

General symptoms

Weight loss for unknown reasons

High body temperature

Heavy sweating at night

General fatigue

Chest pain associated with breathing difficulty.

Fullness and pain of the stomach.

Other symptoms can be as follows:

Lymph nodes near the skin

Lymph nodes of different parts of the surface such as on the neck, in the groin or armpit areas become swollen.


Abdominal lymphoma leads to the swelling of intestines which results in pain, discomfort and vomiting and loss of appetite.


Thymus lymphoma affects the trachea which results in breathing problems.


Primary Brain Lymphomas cause headache, weakness and sometimes seizures.

Diagnosis of non-Hodgkin lymphoma:

When a lymph node is swollen and its location and other behaviour strongly suggests that it can be a cancerous growth a biopsy is done to confirm the disease.


Excisional or incisional biopsy: In this process the whole lymph node is removed from the body by excision and sent for routine biopsy.

Fine needle aspiration (FNA): In this biopsy small specimen is collected via a needle from the tumour growth. The technique might involve computed tomography (CT) scan or an ultrasound. Needle biopsies are less commonly used unless the patient already diagnosed with lymphoma has another area of tumour growth.

Bone marrow aspiration and biopsy: These tests usually done simultaneously, are targeted to detect lymphoma in bone marrow. Hip bone or breast bone are the common choice to withdraw samples. For aspiration, a little amount of liquid bone marrow is sucked out while for biopsy both bone and marrow are collected immediately.

Lumbar puncture (spinal tap): To detect the presence of lymphoma in brain a small amount of cerebrospinal fluid (CSF) is taken in this test.

Pleural or peritoneal fluid sampling: This test is performed to determine the lymphatic cells in pleural fluid (inside the chest) or peritoneal fluid (inside the abdomen).


Cytogenetics test identifies whether there is any kind of abnormalities present in the chromosomes of the lymphatic cells. Microscopic examination is used to detect translocations of chromosomes.

Molecular genetic studies

Two different types of molecular genetics studies are used:

Fluorescent in situ hybridization (FISH): This test involves a certain type of dye which attaches to a special part of the chromosome to identify any change within the DNA of the lymphoma cell.

Polymerase chain reaction (PCR): PCR is a highly sensitive test which examines the role of genes responsible for the rapid growth of the cells.


This test is used to identify the type of lymphoma of the patient. Lymphoma cells are treated with synthetic which reveals the colour change later on.

Flow cytometry

This test is often used as a confirmation of the immunophenotyping of the lymphoma cells. Specific antibodies are given to the biopsy sample and then the sample is treated with laser beam. Emission of light is measured via computer. It distinguishes lymphoma from other non-cancerous diseases.


Cytogenetics test identifies whether there is any kind of abnormalities present in the chromosomes of the lymphatic cells. Microscopic examination is used to detect translocations of chromosomes.

Molecular genetic studies

Two different types of molecular genetics studies are used:

Fluorescent in situ hybridization (FISH): This test involves a certain type of dye which attaches to a special part of the chromosome to identify any change within the DNA of the lymphoma cell.

Polymerase chain reaction (PCR): PCR is a highly sensitive test which examines the role of genes responsible for the rapid growth of the cells.

Other lab tests

Blood tests help to determine the stages of lymphoma. Presence of lactate dehydrogenase (LDH) are much higher in patients with advanced stage lymphomas. Liver and kidney problems as well as the clotting property can also be determined by this test.

Imaging tests : This test is performed to find out the causes of the cancer by x-rays, magnetic fields or radioactive particles.

CT (Computed tomography) scan: CT scan identifies the presence of any abnormal growth in the soft tissue, e.g., head, neck, chest or abdomen.

Magnetic resonance imaging (MRI) scan: Radio waves and magnetic fields are used to determine a specific pattern of the tissues (especially brain and spinal cord) by this test.

Ultrasound: nature and location of the abnormal lymph nodes as well as swelling of the kidney can be identified through ultrasound.

Positron emission tomography (PET) scan: This test is mainly done to follow up the treatment of lymphoma and gives information of the whole body rather than a specific localized area. The test is based on the absorbance of the radioactive sugar by the cancer cells.

Gallium scan: Gallium scan often shows the spreading of lymphoma to the bones and other argans by injecting radioactive gallium into veins.

Bone scan: Bone scan is used to detect not only cancer of bones, but also any other related problems aroused from lymphoma like arthritis and fractures.

Stages of adult non-Hodgkin lymphoma:

Staging of adult NHL can be done in different ways. The most common system is called Ann Arbor staging system. To describe the stages of adult non-Hodgkin lymphoma the terms 'E' and 'S' are often mentioned.

E: "E" describes the presence of cancers in extranodal areas which excludes the lymph nodes.

S: "S" describes the spread of cancer in spleen.

The staging system most often used to describe the extent of non-Hodgkin lymphoma in adults is called the Ann Arbor staging system.

Stage I

The lymphoma involves only one region of the lymph nodes or it can be present in one area of an extra nodal single organ (IE).

Stage II

Patients in this stage have lymphoma in two or more different groups of lymph nodes and they have to be on the same side of the diapharm.

The cancer might spread to a nearby organ of a specific lymph node (IIE). Stage III

Stage III

Patients diagnosed with lymphoma on both sides of the diapharm are in stage III.

Malignancies can also extend to a nearby organ of the lymph nodes (IIIE), into the spleen (IIIS), or both (IIISE).

Stage IV

In stage IV, cancer spreads outside the lymph system like bone marrow, brain, lungs or liver.

Adult NHL can also be classified depending on their fast-growing nature and the area of cancerous growth in the body:

Indolent or aggressive:

Slow growing lymphomas with fewer symptoms can be classified as indolent lymphoma.

Fast growing aggressive lymphomas have severe symptoms. Patients who are HIV-positive are more prone to develop aggressive lymphoma.

Contiguous or noncontiguous:

Contiguous lymphomas involve cancerous growth in the lymph nodes which are adjacent to each other.

If lymphomas are present on the same side of the diaphragm but the lymph nodes are separated then it is referred as noncontiguous lymphoma.

Treatment of adult non-Hodgkin lymphoma:

Standard treatments for non-Hodgkin lymphoma involve the following:


Surgery is not a very popular option for the treatment unless the onset of the lymphoma has been detected in a specific organ like thyroid or stomach and has not undergone metastasis.

Radiation therapy

At the primary stages of lymphoma radiation therapy is the main treatment choice whether for more aggressive types it is given along with chemotherapy. It is a painless procedure which uses high energy x-rays to stop the growth of lymphoma cells. An external machine can be used as the source of the radiation beam or it can be given internally having radioactive substance in different forms. Needles, wires, catheters or seeds are used to place radioactive materials directly onto the site of cancer.