Myeloproliferative Disorders

Myeloproliferative disorders (also called Myeloproliferative neoplasms) are types of slow-growing blood cancers. They are caused by a mutation in stem cells of the bone marrow. This leads to an overproduction of white blood cells, red blood cells and/or platelets. There are several different Myeloproliferative disorders, each with its own characteristics. The primary conditions are: polycythemia vera, essential thrombocytopenia, idiopathic myelofibrosis, and chronic myelogenous leukemia (CML).

Myeloproliferative disorders are serious, but many people are able to control these disorders and live for many years. The prognosis largely depends on the specific disorder. The cause of myeloproliferative disorders is unknown, although many researchers point to genetic conditions such as the Philadelphia chromosome (associated with CML) or environmental exposure to certain harmful chemicals and radiation.

These disorders are often asymptomatic but the most common symptom, shared by several of the different disorders (although not essential thrombocytosis), is an enlarged spleen.

Polycythemia Vera

This disorder occurs when the bone marrow produces too many blood cells – specifically – red blood cells. Almost all people with this disorder carry a blood mutation called JAK2V617F. Polycythemia vera can strike at any age but is most likely to occur in people over 60. Men are twice as likely as women to develop this condition. It is thought that heavy exposure to radiation may increase a person's risk.

General symptoms include fatigue; headache; itchy, blotchy, or painful skin; and vision problems. More specific symptoms include difficulty breathing, stomach aches, bleeding in the nose, gums or stomach, blood in the urine, high blood pressure, and blockage of blood vessels. Blocked blood vessels may lead to heart disease, stroke, or gangrene.

Essential Thrombocytosis

This disorder happens when the body produces too many platelet cells, which help blood to clot. Clots can block blood vessels, leading to heart attack or stroke. Generally, this disorder affects people over the age of 60, although up to 20 percent of people affected are under 40. Women are more likely than men to be affected. Exposure to chemicals or to electrical wiring may increase a person's risk.

Symptoms include headache, bruising, gastrointestinal bleeding, and burning or throbbing in the hands and feet (possibly accompanied by redness and swelling). These symptoms could lead to heart attack or stroke.

Idiopathic Myelofibrosis (Myelosclerosis)

In this disorder, one of the most serious of the group, the bone marrow produces too much collagen or fibrous tissue. This reduces the marrow's ability to produce blood cells. The disorder primarily affects people in their 60s. Men are slightly more likely than women to develop idiopathic myelofibrosis. People who are exposed to petrochemicals and intense radiation are at higher risk.

Symptoms can include fatigue, weight loss, anemia, difficulty breathing, fever/night sweats, and abnormal bleeding.

Chronic Myelogenous Leukemia (CML)

This is a cancer of the bone marrow, producing abnormal granulocytes (a type of white blood cell). This disorder most often strikes people at about the age of 45-50, and is more likely to occur in men. Exposure to heavy doses of radiation may increase the risk.

Symptoms can range from vague discomfort, such as fatigue, loss of appetite, and infection. To more severe complaints, such as fever/night sweats, bone or joint pain, difficulty breathing, gastrointestinal bleeding, and even heart attack or stroke.


Most myeloproliferative disorders cannot be cured, but can be mitigated by various treatments. Surgery is sometimes performed when the spleen becomes dangerously enlarged or painful. Bone marrow transplants may be appropriate for people with CML. Treatment with phlebotomy (removing some blood from the body) may decrease the risk of stroke in people with polycythemia vera. Treatment may also include the use of nutritional supplements.



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