Essential Thrombocythemia

Question 1

Essential thrombocythemia (ET)

Answer 1

Essential thrombocythemia (ET) is a BCR-ABL1-negative myeloproliferative neoplasm (MPN) characterized by excessive, clonal platelet production.

Unexplained persistent thrombocytosis

Question 2

Diagnosis Essential thrombocythemia

Answer 2

Unexplained persistent thrombocytosis

Bone marrow biopsy classically shows normocellularity or moderate hypercellularity for age and trilineage growth with prominent large to giant megakaryocytes with abundant mature cytoplasm, and deeply lobulated and hyperlobulated nuclei

●JAK2 mutation – 60 to 65 percent
●CALR mutation – 20 to 25 percent

Question 3

Risk stratification of Essential thrombocythemia

Answer 3

●High-risk disease – History of thrombosis at any age and/or age >60 with a JAK2 V617F mutation
●Intermediate-risk disease – Age >60, no JAK2 mutation detected, and no history of thrombosis
●Low-risk disease – Age ≤60 with JAK2 mutation and no history of thrombosis
●Very low-risk disease – Age ≤60, no JAK2 mutation detected, and no history of thrombosis

Question 4

Treatment of Essential thrombocythemia

Answer 4

The goals of ET management are to alleviate symptoms and minimize complications of the disease

treat with aspirin to prevent occlusive events

hydroxyurea if platelet count exceeds 1000 or thrombotic events

if thrombosis addition of anticoagulation

interferon is an option if pt is pregnant

Question 5

Compication of persistent untreated thrombocythemia

Answer 5

von willibrands disease

Question 6

Anagrelide

Answer 6

Anagrelide works by inhibiting the maturation of platelets from megakaryocytes

good cytoreductive agent but not shown to be better than hydroxyurea for treatment of essential thrombocythemia
worse side effects: cardiac toxicity

contraindicated in pregnancy