Prenatal manifestation of Transient Abnormal Myelopoiesis in a genotypically normal fetus: case report and review of the literature

Abstract

Background: Congenital malignancies are unusual fetal conditions and therefore the data on their prenatal manifestation is limited. Transient abnormal myelopoiesis (TAM) is a hematologic disorder characteristic for babies with trisomy 21 and base on transient appearance of the blast cells in peripheral blood. This paper presents prenatal manifestation of congenital TAM in a genotypically normal newborn and reviews the literature on prenatal manifestation of this disorder. Case presentation: A pregnant woman in her third pregnancy referred herself to the hospital for reduced fetal movements at 30 weeks of gestation. Admission’s ultrasound scan showed an increased middle cerebral artery peak systolic velocity (MCA PSV) together with hepatomegaly. The patient was admitted to the labor ward for cardiotocography monitoring which showed an acute fetal distress with repeated unprovoked decelerations. An emergency cesarean section was conducted and a phenotypically normal female newborn with low Apgar score was delivered. Further examination of peripheral blood revealed anemia and leukocytosis with high blast proportion. A bone marrow aspirate revealed 70.2% of blasts in a sample with an abnormal karyotype of 47,XX+21. Cytogenetic analysis of blasts with later microarray comparative genomic hybridizationconfirmed the presence of GATA1 mutation. However, the buccal smear showed a normal karyotype in the infant. The disease was classified as TAM. The literature review together with the case presentation showed that increased MCA PSV and hepatosplenomegaly are important risk factors of death in fetuses with TAM. Conclusions: Our study demonstrates a rare case of prenatal manifestation of TAM in genotypically normal neonate. Obstetricians should pay attention to symptoms like high MCA PSV and hepatosplenomegaly as possible causes of fetal hematological disorders and differentiate it with infection or isoimmunization.