Find information on medical topics, symptoms, drugs, procedures, news and more, written in everyday language.

* This is the Consumer Version. *

Overview of Myeloproliferative Disorders

by Jane Liesveld, MD, Patrick Reagan, MD

In myeloproliferative disorders (myelo = bone marrow, proliferative = rapid multiplication), the blood-producing cells in the bone marrow (precursor cells) develop and reproduce excessively or are crowded out by an overgrowth of fibrous tissue. Typically, these disorders are acquired and not inherited, although rarely there are families in which several members have these disorders.

Three major myeloproliferative disorders are

In a small number of people, a myeloproliferative disorder progresses or transforms to leukemia, which is a cancerous (malignant) disorder.

Major Myeloproliferative Disorders


Bone Marrow Characteristics

Blood Characteristics

Polycythemia vera

Increased number of cells that produce the circulating blood cells

Increased number of red blood cells

Often, increased number of platelets and white blood cells


Excess fibrous tissue

Increased number of immature red and white blood cells

Misshapen red blood cells

Decreased overall number of red blood cells (anemia)

The numbers of white blood cells and platelets often eventually decrease, but in some people they increase


Increased number of cells that produce platelets (megakaryocytes)

Increased number of platelets

Resources In This Article