Cancer is a group of many related diseases. All cancers begin in cells
, the body's basic unit of life. Cells make up tissues, and tissues make up the organs of the body.
Normally, cells grow and divide to form new cells as the body needs them. When cells grow old and die, new cells take their place. Sometimes this orderly process goes wrong. New cells form when the body does not need them, and old cells do not die when they should. These extra cells can form a mass of tissue called a growth or tumor
Tumors can be benign or malignant.
Benign tumors are not cancer.
Usually, doctors can remove them. Cells from benign tumors do not spread to other parts of the body. In most cases, benign tumors do not come back after they are removed. Most important, benign tumors are rarely a threat to life.
Malignant tumors are cancer.
They are generally more serious. Cancer cells can invade and damage nearby tissues and organs. Also, cancer cells can break away from a malignant tumor and enter the bloodstream or the lymphatic system. That is how cancer cells spread from the original (primary
) tumor to form new tumors in other organs. The spread of cancer is called metastasis
Although lymphomas are generally divided into two general types, Hodgkin and Non-Hodgkin, there are actually many different types of this cancer, including:
Multiple Myeloma and Other Plasma Cell Neoplasms
Mycosis Fungoides and the Sézary Syndrome
Primary CNS Lymphoma
Lymphoma begins in the lymphocytes of the immune system and presents as a solid tumor of lymphoid cells. The cancerous cells often originate in lymph nodes, presenting as an enlargement of the node (a tumor). There are many types of lymphomas, and in turn, lymphomas are a part of the broad group of diseases called hematological neoplasms.
The lymph system (also known as the lymphatic system) is composed mainly of lymphoid tissue, lymph vessels, and a clear fluid called lymph.
Most of the cells in lymphoid tissue are lymphocytes, a type of white blood cell. The 2 main types of lymphocytes are B lymphocytes (B cells) and T lymphocytes (T cells). Both types can develop into lymphoma cells, but B-cell lymphomas are much more common than T-cell lymphomas in the United States.
The major sites of lymphoid tissue are:
Lymph nodes are bean-sized organs throughout the body that are connected by a system of lymphatic vessels. These vessels are like veins, except that instead of carrying blood, they carry lymph and immune system cells.
The spleen is an organ under the lower part of the rib cage on the left side of the body. The spleen makes lymphocytes and other immune system cells to help fight infection.
The thymus lies behind the upper part of the breastbone and in front of the heart.
Adenoids and Tonsils:
These are collections of lymphoid tissue located at the back of the throat.
The stomach and intestines as well as many other organs also contain lymphoid tissue.
The bone marrow makes red blood cells, blood platelets, and white blood cells. Lymphomas sometimes start from bone marrow lymphocytes.
Hodgkin Disease or Lyphoma is named after Dr. Thomas Hodgkin, who first recognized the disease in 1832. In the year 2009, 8,510 new cases of Hodgkin Disease were diagnosed in the United States.
Although both children and adults can get Hodgkin Disease, most cases are found in two prevalent age groups. Early adulthood (ages 15 to 40) and late adulthood (after age 55) are most at risk.
Cancer cells in Hodgkin Disease are unique. Called Reed-Sternberg cells
(or Hodgkin cells), they are an abnormal type of B lymphocyte. There are two main classifications of Hodgkin Disease.
Classic Hodgkin Disease (CHL)
Classical Hodgkin Disease (HD) accounts for about 95% of all cases of this type of cancer. About 20% to 25% of people with CHL in the United States and Western Europe have also had the Epstein-Barr virus ( virus that causes infectious mononucleosis).
CHL also has several subcategories: Nodular Sclerosis Hodgkin lymphoma, Lymphocyte Rich Classical Hodgkin lymphoma, Mixed Cellularity Hodgkin Lymphoma and Lymphocyte Depleted Hodgkin Lymphoma.
Nodular Lymphocyte Predominant Hodgkin Disease
Nodular Lymphocyte Predominant Hodgkin disease (NLPHD) accounts for about 5% of Hodgkin disease. This type is more common in men than women, and it mostly involves lymph nodes in the neck and under the arm.
All types of Hodgkin disease are cancer because as they grow they can press on, spread into, and attack and destroy normal tissue.