Major Myeloproliferative Neoplasms

Chronic myeloid leukemia

Increased number of mature and immature white cells

Increased number of a certain type of white blood cell (granulocytes)

Sometimes increased number of platelets

Polycythemia vera

Increased number of cells that produce the circulating blood cells

Increased number of red blood cells

Usually, increased number of platelets, white blood cells, or both

Primary myelofibrosis

Excess fibrous tissue replacing blood-producing cells

Decreased number of red blood cells (anemia)

Misshapen red blood cells

Variable numbers of white blood cells and platelets, often increased early and decreased later in the course of the disease

Primary (essential) thrombocythemia

Increased number of cells that produce platelets (megakaryocytes)

Increased number of platelets