A group of neoplastic diseases primarily involving the bone marrow and characterized by an abnormal proliferation of white blood cells (leukocytes) are known as leukemias. In acute forms of leukemia, the disease strikes suddenly and progresses rapidly, whereas chronic forms are much more insidious and gradual in their development.

Leukemias are generally classified based upon the precise type of white blood cells they involve in addition to whether or not they are acute or chronic. Thus, since normal, mature white blood cells form from stem cells in the bone marrow, a granulocytic leukemia is one that arises from stem cells that in a healthy individual would generate granulocytes, the most prevalent of the three basic leukocyte types (the others are lymphocytes and monocytes). Granulocytic leukemia is also sometimes referred to as myelogenous, nonlymphocytic, or myelocytic leukemia.

Acute granulocytic leukemia is a common form of adult-onset leukemia, with more than an estimated 10,000 American men and women being diagnosed with the disease each year. The risk of developing acute granulocytic leukemia increases with age, and men are more susceptible to it than women. The average age of an individual diagnosed with the disease is 65. In most cases, the cause of the disease is never identified, but in some individuals acute granulocytic leukemia has been associated with exposure to radiation or certain chemicals, such as benzene. Chromosomal abnormalities are also believed to play a role in some cases of the cancer and certain genetic diseases, such as Down syndrome and Shwachman-Diamond syndrome, have been linked to an increased risk of developing acute granulocytic leukemia. A few instances of families with surprisingly high incidence of the disease have also been observed.

The acute form of granulocytic leukemia and other acute varieties of leukemia predominantly involve white blood cells that are not yet fully formed, as opposed to chronic leukemia, which due to its slower onset allows a larger number of more mature leukocytes to form. The abnormal mature cells found in patients with chronic leukemia are usually able to carry on some of the normal functions of white blood cells, unlike immature leukocytes, and therefore, the symptoms of the disease do not develop as quickly as they do in individuals with acute leukemia. Patients with leukemia also often experience an increase in total leukocyte count, though in some cases the count may be unchanged or even decreased. The rare individuals with leukemia who do not exhibit abnormal cells of some type in their blood are said to have aleukemic leukemia. For the disease to be recognized in such individuals, an assessment of the bone marrow must take place.

Symptoms of acute granulocytic leukemia, which result from the body not producing enough healthy blood cells, vary, but frequently include fatigue, pale skin, fever, loss of appetite, sweating, joint pain, increased infections, rash, slowed healing, and bruising and bleeding easier than normal. In some cases, abnormal blood cells may accumulate in the central nervous system, in which case the disease may also manifest itself in the form of headaches, confusion, vomiting, poor motor control, and seizures. Treatment of acute granulocytic leukemia most commonly consists of chemotherapy, which is sometimes utilized in conjunction with a bone marrow transplant. Modern medicine has greatly improved the prognosis of patients with the disease, who without treatment have a life expectancy of only about 3 to 4 months.

Granulocytic Leukemia at 20x Magnification - Approximately 70 to 80 percent of patients treated for acute granulocytic leukemia experience complete remission, though a significant portion of these individuals may suffer a relapse. In the United States, an estimated 20 to 30 percent of individuals are free of the disease five years after they have been diagnosed, at which point they are regarded as permanently cured.