Chronic myeloid neoplasms
Transient abnormal myelopoiesis associated with Down syndrome

Topic Completed: 1 August 2011

Revised: 3 September 2019

Copyright: 2002-2019,, Inc.

PubMed Search: Transient abnormal myelopoiesis associated with Down syndrome

Nikhil Sangle, M.D.
Page views in 2018: 593
Page views in 2019 to date: 369
Cite this page: Sangle N. Transient abnormal myelopoiesis associated with Down syndrome. website. Accessed September 18th, 2019.
Definition / general
  • Also called transient abnormal myelopoiesis, transient leukemia
  • Affects 10% of newborns with Down syndrome
  • Resembles congenital acute leukemia; occurs within first days of life with numerous blasts in peripheral blood, more than those in marrow
  • High rate of spontaneous resolution; usually resolves in 2 - 14 weeks in neonates, but 20 - 30% progress to AML-M7 [FAB] (acute megakaryoblastic leukemia) within 3 years
  • Early death in 17%, is associated with high WBC at diagnosis, increased bilirubin and liver enzymes, failure to normalize WBC (Blood 2006;107:4606)
  • Rarely occurs with trisomy 21 but without Down syndrome (Arch Dis Child Fetal Neonatal Ed 1998;79:F215)
  • Associated with hepatic fibrosis (J Clin Pathol 1995;48:973)
  • WBC up to 100K with 30 - 50% blasts, nucleated red blood cells, micromegakaryocytes, thrombocytopenia
Case reports
Microscopic (histologic) description
  • Bone marrow: blasts have moderate basophilic cytoplasm with coarse azurophilic granules resembling those in basophils, cytoplasmic blebbing suggestive of megakaryoblasts; round to slightly irregular nuclei; also promegakaryocytes, micromegakaryocytes, dyserythropoiesis
Microscopic (histologic) images

Images hosted on other servers:

Peripheral blood:

Various images and stains

Blasts in TMD of Down syndrome

Erythroid blasts with PAS+ granules

Positive stains
Flow cytometry images

Images hosted on other servers:

TMD with erythroid differentiation in Down syndrome

Molecular / cytogenetics description
Differential diagnosis
  • Congenital leukemia: clinically aggressive
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