Cystic hygroma in fetuses with normal and aneuploid karyotypes

Abstract

Introduction. Cystic hygroma is a vascular-lymphatic malformation and can occur either as an isolated finding or as a part of syndrome (chromosomal abnormality; Noonan, Smith–Lemli–Opitz, Escobar, Fanconi pancytopenia syndromes). The incidence of cystic hygroma is about 1:1000–1:6000 births. Objective: The analysis of the ultrasonographic and karyotyping data of fetuses with cystic hygroma. Methods. A complete fetal sonographic examination was performed, followed by fetal karyotyping. For cytogenetic analysis of biopsy samples a direct method of processing the villi was used and for fetal blood a halfmicromethod. Results. A total of 48 (0,7%) fetuses with cystic hygroma were identified in 6919 high-risk pregnancies referred for fetal karyotyping. Cystic hygroma was diagnosed in 50% of the cases at 12–14 weeks of gestation. A karyotype abnormality occurred in 29 (60,4%) of fetuses, including trisomy 21 (20,7%), monosomy X (62,1%), trisomy 18 (10,3%), and other (6,9%). Despite well-known association between maternal age and frequency of aneuploidy, there were only 4 (13,8%) pregnant women over 35 years among diagnosed aneuploid cases. The proportion of pregnant women under 25 years was 2 times higher than in other age groups among euploid fetuses with cystic hygroma. Besides hygroma, associated congenital anomalies were observed in 12 (63,2%) of 19 fetuses with normal karyotype. Among them the most frequently diagnosed were cardiac abnormalities – 10 (83,3%) cases. Conclusion. Cystic hygroma is associated with high rates of karyotype abnormality, major congenital malformations. Monosomy X was the most common form (62,1%) among aneuploid cases of cystic hygroma (n= 29). Only 7 (14,6%) fetuses were euploid and without ultrasonographic detectable structural anomalies.