Early sonographic diagnosis of fetal cystic hygroma colli.

Fetal cystic hygroma colli (FCHC) is a congenital malformation of the lymphatic system which develops as a result of failure of the communication between the jugular lymphatic canal and the internal jugular vein. The diagnosis is usually made by ultrasound in the second trimester of pregnancy by the demonstration of a multiseptate, thin-walled cystic mass appearing posterolaterally in position to the fetal head and neck region. In this report we present two cases of FCHC diagnosed by transabdominal ultrasound in the first trimester of pregnancy. In one case, chorionic villus sampling revealed a 45,X karyotype, the fetus became progressively hydropic and died at 15 1/2 weeks. In the other, the spontaneous resolution of a nonseptated FCHC in a fetus with normal karyotype was documented, resulting in the delivery of a healthy infant a term. Fetal karyotyping, a careful search for other anomalies that may affect fetal survival, and a close sonographic follow-up in cases of FCHC are advocated for an accurate diagnosis and genetic counselling.