Types of Leukemias

Leukemia is a cancer of the blood or bone marrow defined as an abnormal proliferation of white blood cells. There are four major types of leukemias: Acute Lymphoblastic Leukemia (ALL), Acute Myelogenous Leukemia (AML), Chronic Lymphocytic Leukemia (CLL), and Chronic Myelogenous Leukemia (CML).  

A leukemia is taken into consideration as a possible diagnosis when a blood test reveals a higher than normal number of circulating blood lymphocytes, bone marrow infiltrates of leukemic cells, and/or an increase in the number of "band cells" commonly called a Shift-To-The-Left.  

An acute leukemia is commonly associated with a younger age and a short and drastic course. In an acute leukemia, the proliferation of immature white cells out-competes normal blood cells. If not treated immediately, the immature blood cells can spill into the blood stream and travel to major bodily organs causing severe and irreversible damage to those organs.  

A chronic leukemia is characterized by an older population of patients with a longer and less devastating course. In chronic leukemia, relatively mature, but still abnormal white blood cells over-proliferate and out-compete normal blood cells, yet at a much slower pace and with much less devastating results. As such, a chronic leukemia can take years to progress to a more dangerous form.

Some common symptoms of lymphocytic leukemias are swollen lymph nodes and splenomegaly.  In addition, hypertrophy of the gums may be seen in children with leukemias.  

Acute Lymphoblastic Leukemia

It more commonly presents in children less than 15 years of age, but the most common ages are between 2-4 years old. A characteristic of ALL is the presents of cells called lymphoblasts, and pre-T and pre-B cells. It has a good prognosis as it is most responsive to therapy. But if not caught in time it can spread to the Central Nervous System and the testes. The prognosis for ALL for children has become very good in recent years.

Acute Myeloid Leukemia

Characterized by presence of "Auer rods" and myeloblasts. Auer rods are peroxidase-positive cytoplasmic inclusions in granulocytes and myeloblasts. A release of Auer rods with treatment of AML can precipitate a Disseminated Intravascular Coagulation (DIC) reaction, which can be deadly. It prevalent more commonly in adults, but its age range is anywhere from 5 to 40-years-old. 

Chronic Lymphoblastic Leukemia

More common in older adults greater than 60 years of age. It is characterized by presence of swollen lymph nodes (lymphadenopathy), enlargement of spleen and liver, increase in smudge cells in peripheral blood smear due to the lysis of the lymphocytes upon staining and preparation for microscopy view. It is commonly associated with the warm antibody autoimmune hemolytic anemia. 

Chronic Myelogenous Leukemia

Defined by the Philadelphia chromosome (Translocation of 9;22, bcr-abl gene). It is characterized by prolifereation of myeloid stem cells and presence of increased neutrophils. Splenomegaly may be present. CML has a bad prognosis as it is considered uncurable. Most often, patients are diagnosed in their seventies when they come to the doctor with a common complaint of tiredness. At that point, not much can be done.

Copyright ? 2009 - Yana G. Yevstegneeva, 2nd-year Medical Student. All Rights Reserved Worldwide.