Leukemia

Leukemia is a type of blood cancer that begins in the bone marrow. Bone marrow is the soft tissue in the center of the bones, where blood cells are produced.

The term leukemia means white blood. White blood cells (leukocytes) are used by the body to fight infections and other foreign substances. Leukocytes are made in the bone marrow.

Leukemia leads to an uncontrolled increase in the number of white blood cells.

The cancerous cells prevent healthy red cells, platelets, and mature white cells (leukocytes) from being made. Life-threatening symptoms can then develop as normal blood cells decline.

The cancer cells can spread to the bloodstream and lymph nodes. They can also travel to the brain and spinal cord (the central nervous system) and other parts of the body.

Leukemia can affect children and adults.

Leukemias are divided into 2 major types:

  • Acute (which progresses quickly)
  • Chronic (which progresses more slowly)

The main types of leukemia are:

Bone marrow aspiration

A small amount of bone marrow is removed during a bone marrow aspiration. The procedure is uncomfortable, but can be tolerated by both children and adults. The marrow can be studied to determine the cause of anemia, the presence of leukemia or other malignancy, or the presence of some "storage diseases" in which abnormal metabolic products are stored in certain bone marrow cells.

Acute lymphocytic leukemia - photomicrograph

This picture shows the darkly-stained lymph cells (lymphoblasts) seen in acute lymphocytic leukemia (ALL), the most common type of childhood leukemia.

Auer rods

Note multiple Auer rods which are found only in acute myeloid leukemias, either myeloblastic or monoblastic. These rods consist of clumps of azurophilic granule material.

Chronic lymphocytic leukemia - microscopic view

This is a microscopic view of bone marrow from a person with chronic lymphocytic leukemia; it shows predominantly small, mature lymphocytes.

Chronic myelocytic leukemia - microscopic view

This high-power microscopic view of a blood smear from a person with classical CML shows predominantly normal-appearing cells with intermediate maturity.

Chronic myelocytic leukemia

Oil immersion field demonstrating myeloid cells of all degrees of maturity.

Chronic myelocytic leukemia

Low power view showing marked hypercellularity with a broad-spectrum of myeloid and erythroid cell types and marked myeloid hyperplasia.

Cryoglobulinemia - of the fingers

Cryoglobulinemia is caused by an abnormal protein that is occasionally found in the blood of people with multiple myeloma, leukemia, and certain forms of pneumonia. It causes blood to gel at low temperatures. In this picture, cryoglobulinemia has reduced blood flow in the fingers so much the fingers have turned dark; the black areas are gangrene resulting from lack of blood flow.

Antibodies

Antigens are large molecules (usually proteins) on the surface of cells, viruses, fungi, bacteria, and some non-living substances such as toxins, chemicals, drugs, and foreign particles. The immune system recognizes antigens and produces antibodies that destroy substances containing antigens.