According to the University of Virginia School of Medicine's Pathology Thread, myelocytes sometimes are found in peripheral blood in combination with a general increase in the number of white blood cells, a condition doctors call leukocytosis. This condition is related to many causes, including infection, inflammation, tissue damage, drugs, toxins, emotional stress, metabolic disturbances, blood disorders and some cancers.
Doctors use various methods to determine the cause of myelocytes in the blood. The shape and size of the cells is important, as is how the cells react to different reagents, or stains. According to the University of Virginia School of Medicine, the presence of many different types of immature cells, such as myelocytes, promyelocytes and metamyelocytes, indicates a leukemoid reaction. This reaction may be due to malignancy, but also may result from stress, infection or the effects of corticosteroids or other drugs.
Chronic myelogenous leukemia is one form of cancer that results in an increased number of circulating myelocytes, usually accompanied by a large number of other immature cells and an increased platelet count, says MedlinePlus. Related to a genetic abnormality known as the Philadelphia chromosome, CML is a slowly progressing disease that people often survive with for many years. At first, symptoms are mild or nonexistent, but as the disease progresses, a swollen abdomen, tiredness, bruising, night sweats and fever appear. Treatment is aimed at controlling the protein made by the Philadelphia chromosome and, if necessary, decreasing the total white blood count.