Acute megakaryoblastic leukaemia

This bone marrow smear is from a 71-year-old woman with AML-M7.  The cellularity of bone marrow was reduced, with 48% of blasts (50% of the blasts are of megakaryocyte lineage, yellow arrows).

This image shows a large megakaryoblast with pseudopod formations, the so-called blebs (yellow arrows) and nuclear protrusions (red arrows). The cytoplasm is basophilic with fine azurophilic granules.

The blasts show reactivity with acid phosphatase stain (yellow arrow). Megakaryoblasts express platelet glycoproteins CD41 (IIb/IIIa) and CD61 (IIIa).