Macrothrombocytopaenia

Macrothrombocytopenia

Platelets are very small blood cells (1.5–3 μm), which play a major role in primary haemostasis and in coagulation mechanisms.

When large platelets are seen in the peripheral blood film, assessment of the platelet morphology and the presence of other cell lines for other features suggestive of the underlying diagnosis.

Differential Diagnosis for Macrothrombocytopenia

1. Bernard Soulier
2. MYH9 Related Disorders
3. Grey Platelet Syndrome
4. GATA1 associated with Down Syndrome
5. Platelet-type pseudo-vWD
6. ITP

Bernard Soulier

Bernard Soulier is an autosomal recessive disorder characterized by thrombocytopenia, giant platelets and marked platelet dysfunction. This is due to the dysfunction or absence of the platelet glycoprotein Ib-IX-V.

Blood film of a patient with Bernard Soulier. Note the giant platelets which are almost the same size as the RBC.

May-Hegglin

May-Hegglin is a MYH9 disorder, where there is a mutation of the nonmuscle myosin heavy chain gene. All MYH9-related disorders (May-Hegglin anomaly and Fechtner, Epstein, and Sebastian syndromes) are associated with macrothrombocytopenia.

Blood film from two patients with MYH9-related disease. Note the large platelets and Dohle bodies found in the neutrophils.

Other Resources

• ASH image bank: Macrothrombocytopenia and neutrophils with Döhle-like bodies
• ASH image bank: Gray platelet syndrome: macrothrombocytopenia with deficient a-granules
• ASH image bank: Bernard-Soulier syndrome