Imbalance of angiogenic factors and avascular edematous cystic villi in a trisomy 13 pregnancy: a case report.

The incidence of pre-eclampsia is significantly higher in trisomy 13 pregnancies than in normal pregnancies. Soluble fms-like tyrosine kinase-1 (sFlt-1), located on chromosome 13, is an anti-angiogenic molecule derived from the placenta and contributes to the pathogenesis of pre-eclampsia. Elevated sFlt-1 and reduced placental growth factor (PlGF) are associated with trisomy 13 pregnancies and may play a pathogenic role in the subsequent development of pre-eclampsia. Here we present a case of a trisomy 13 pregnancy without any signs of pre-eclampsia that showed alterations in circulating angiogenic factors and abnormal placental appearance. The placenta developed edematous changes and contained multiple small cysts. Histology of the placenta confirmed avascular edematous cystic villi and did not show the typical appearance of a partial mole or mesenchymal dysplasia. The sFlt-1/PlGF ratio in maternal serum (134) was much higher than that in gestational age-matched women who were normotensive (2.9-7.2; mean, 5.0). Immunostaining for Flt-1 and endoglin was more intense in our case compared with gestational age-matched controls, and at a similar level to a case of pre-eclampsia. Placental findings that showed avascular edematous cystic villi in our case may be associated with angiogenic imbalance involved in the pathogenesis of pre-eclampsia in trisomy 13 pregnancies.