There are three major forms of blood cancer--leukemia, lymphoma and multiple myeloma--each of which is classified according to the type of cell involved and other criteria related to onset and outcome.
Leukemia
Leukemia is a malignancy of the white blood cells (WBCs) in which there is an abnormal increase in the number of WBCs. As they proliferate, they crowd out and replace the normal cells. Leukemia is classified under two categories--type of WBC involved and onset/progression--and these are combined to name the four types of leukemia. All types of leukemia can manifest in non-specific symptoms that include weakness, fatigue, decreased appetite, anemia, swollen and an enlarged liver or spleen.
Classifications of Leukemia
Acute leukemia presents with more immediate and severe symptoms such as anemia and bleeding. It also progresses at a rapid rate. Chronic leukemia may have no symptoms at first and it progresses so slowly that people with this disease can live a long time even without treatment.
The two types of cells involved are lymphocytes and myelocytes. In lymphocytic leukemia, there is uncontrolled growth of lymph cells. These may be adult or immature cells. Myelocytes are young, immature cells in the bone marrow.
Four Types of Leukemia
Acute lymphocytic leukemia (ALL) is the childhood leukemia. In this type young lymphocytes, called lymphoblasts, are malignant. In addition to the non-specific symptoms, bleeding, easy bruising, and infection are present. Additionally, as the overgrowth of cancerous cells accumulates, the lymph nodes, liver and spleen become enlarged.
Chronic lymphocytic leukemia (CLL) is rare under in people the age of 30--most cases are diagnosed in people over 60. In CLL the adult lymphocytic cells are malignant. At first there may be no symptoms but the defective lymphocytes have an abnormally long life span and as the disease spreads, infections occur and the skin is affected.
Acute myelocytic leukemia (AML) represents half of the leukemia diagnosed in teenagers and young adults. It's also the most common form of leukemia in adults. Symptoms are the same as those found in ALL.
Chronic Myelocytic Leukemia (CML) can strike at any age, but it is uncommon before the age of 10 and is typically diagnosed between 45 and 55. Just like CLL, progression is slow but eventually it enters a more proliferative phase and can evolve into an acute phase called a blast crisis. In a blast crisis, the normal elements found in the blood are almost entirely replaced by immature blast cells.
Lymphoma
Lymphoma is a cancer of the lymph cells--the lymphocytes--in which they grow abnormally and out of control. Doctors once thought there was a distinct difference between lymphoma and lymphocytic leukemia, but with scientific advances they are learning that the differences are not so specific. However, they are still classified as different cancers and lymphoma is further categorized as either Hodgkin's or non-Hodgkin's.
Hodgkin's Lymphoma
Hodgkin's is usually diagnosed between the ages of 15 to 40 or in people older than 50 and is found more frequently in men than women. Hodgkin's is more localized with less spreading of the malignant cells. The cancer primarily involves the lymph nodes, spleen, and sometimes the liver. Treatment of this form of blood cancer is successful 75 percent of the time. The symptoms include enlarged lymph nodes, fever, night sweats, weight loss, and enlargement of the spleen and liver. Pruritus, which is itchy spots caused by irritated nerves, may also be present.
Non-Hodgkin's Lymphoma
Representing the majority lymphomas, non-Hodgkin's lymphoma (NHL) is the sixth most common cancer in the U.S. NHL is leukemia-like with the cancer spreading in 50 percent of children and 20 percent of adults. NHL is further categorized into low, intermediate, or high grade malignancies. Low means slow growing, and high refers to aggressive growth.
Multiple Myeloma
This is a cancer of the bone marrow in which there is uncontrolled growth of plasma cells. Cancerous plasma cells collect in the bones causing them to swell and making them weak. The symptoms include anemia, bleeding, infections, and weakness. Also, increased levels of one type of antibody--immunoglobulin--causes the blood to become too thick. This is a rare form of blood cancer that is diagnosed more often in men and primarily in people over the age of 60.
Tags: lymph nodes, lymphocytic leukemia, most common, , blast crisis