Introduction
Acute megakaryoblastic leukemia (AMKL) is a subtype of acute myeloid
leukemia (French-American-British classification AML-M7) which is
defined as 50% or more of total blast cells in a bone marrow sample
being attributed to megakaryoblasts1. As with other
subtypes of acute myeloid leukemia (AML), the total blasts of more than
20% of all nucleated cells in the peripheral blood film and bone marrow
also applies to AMKL. AMKL was first described by Von Boros, et al in
1931. AMKL may occur as de novo, or secondary to a myelodysplastic
syndrome (MDS) or myeloproliferative neoplasm (MPN). AMKL shows a
bimodal age distribution; being common in children aged 1-3 and elderly
adults. Down syndrome (DS) individuals have a 500-fold increase in
contracting AMKL, and they have a better prognosis as compared to non-DS
individuals2. There is also an association between
mediastinal germ cell tumours (GCT) and AMKL in young male children with
many of them being diagnosed with AMKL a few months
later3. AMKL is known to be associated with extensive
myelofibrosis resulting in a frequent dry bone marrow aspiration. This
disease demonstrates a poor prognosis with the median survival of less
than 6 months from diagnosis4. Here, we report an
unusual case of transformation of myelodysplastic syndrome to acute
megakaryoblastic leukemia in a middle-aged male who followed an
aggressive course of illness.