Leukemia is cancer of the blood cells, usually the white blood cells. Leukemic cells look different than normal cells and do not function properly.
There are four main types of leukemia, which can be further divided into subtypes. When classifying the type of leukemia, the first steps are to determine if the cancer is:
- Lymphocytic or myelogenous leukemia
Cancer can occur in either the lymphoid or myeloid white blood cells. When the cancer develops in the lymphocytes (lymphoid cells), it is called lymphocytic leukemia. When the cancer develops in the granulocytes or monocytes (myeloid cells), it is called myelogenous leukemia.
- Acute or chronic leukemia
Leukemia is either acute or chronic. In acute leukemia, the new or immature cancer cells, called blasts, remain very immature and cannot perform their functions. The blasts increase in number rapidly, and the disease progresses quickly. In contrast, chronic leukemia progresses gradually: there are some blast cells present, but they are more mature and are able to perform some of their functions. The cells grow more slowly, and the number increases less quickly.
Based on these findings, the leukemia is then classified into one of the four main types of leukemias below. There are other types and subtypes of leukemias as well.
- Acute myelogenous leukemia (AML)
- Chronic myelogenous leukemia (CML)
- Acute lymphocytic leukemia (ALL)
- Chronic lymphocytic leukemia (CLL)
Symptoms can vary, but the following are the most common symptoms of leukemia:
- Increased susceptibility to infections and fevers
- Loss of appetite
- Loss of weight
- Swollen or tender lymph nodes, liver, or spleen
- Petechiae - tiny red dots under the skin that are the result of very small bleeds
- Swollen or bleeding gums
- Bone or joint pain
In addition, acute leukemia may cause the following:
- Loss of muscle control
- Swollen testicles
- Sores in the eyes or on the skin
Chronic leukemia may affect the skin, central nervous system, digestive tract, kidneys, and testicles.
The symptoms of acute and chronic leukemias may resemble other blood disorders or medical problems. Always consult your physician for a diagnosis.