Myeloproliferative Disorders

Question 1

What are some things that apply to all myeloproliferative disorders?

Answer 1

Neoplasm of mature myeloid cells

Hyperuricemia/gout: overproduction of cells leads to increased degradation of nuclei, leading to increased serum uric acid content.

All myeloid cells increase, but one predominates.

Question 2

Chronic Myelogenous Leukemia (CML)

Answer 2

Increased neutrophils/granulocytes

Basophilia

BCR-ABL fusion: t(9;22) (Philadelphia Chromosome)

Splenomegaly

Question 3

Polycythemia Vera

Answer 3

Increased RBCs

JAK2 mutation

Decreased EPO (due to elevated RBCs)

Hyperviscous blood –> blurry vision, headache, thrombosis, flushed face

Increased histamine release from mast cells: itching after bathing and peptic ulcers

Question 4

Essential Thrombocythemia

Answer 4

Increased platelets. Many are dysfunctional

JAK2 mutation

Increased bleeding/thrombosis.

Splenomegaly

Platelets do not have nuclei –> no increased risk for gout

Question 5

Primary Myelofibrosis (MMM)

Answer 5

Increased megakaryocytes

JAK2 mutation

Megakaryocytes have excess PDGF –> increased fibrosis in BM

Bone marrow have become too fibrosed for hematopoiesis –> splenomegaly

Tear drop RBCs present (stretched by fibrosis)

Increased infection, thrombosis and bleeding. Splenic infarcts common.