Transient abnormal myelopoiesis (TAM) is a phenomenon that can happen in the fetuses or neonates with trisomy 21. The condition can mimic leukemia.
Epidemiology
The estimated incidence is at ~10% of newborns with trisomy 21 3.
Radiographic features
Antenatal ultrasound
In the context of known trisomy 21, features that may suggest towards the diagnosis include:
- development of fetal hepatomegaly/fetal hepatosplenomagaly: tends to give hypoechoic hepatomegaly 4,5
Treatment and prognosis
Although it can closely mimic leukemia, most neonates who survive to 4-8 weeks show complete remission. There is however a very high risk development of acute myeloid leukemia around 2-3 years of age.