OBJECTIVE: To develop an algorithm for the prenatal management of patients when a cystic hygroma is diagnosed by ultrasonography. METHODS: We report a personal series of 25 cases diagnosed between 10 and 23 weeks gestation and a review of the literature comprising a total of 999 cases. We focused on the etiologies and the value of various prognostic factors in the management of cystic hygromas. These include karyotype, alpha-fetoprotein levels, sonographic findings in the fetus and within the hygroma itself, and natural history. RESULTS: According to the literature, fetal chromosomal abnormalities were associated with cystic hygromas in 62% of the cases. Turner's syndrome remains the most common (33%) but Down's syndrome, Trisomy 18 and Trisomy 13 are not rare (15, 7 and 2%). Others have Mendelian abnormalities. The prognosis remains gloomy. The literature reports that only 9% of cases result in healthy children with normal karyotypes. The remaining 91% are either terminated (89%) or liveborn (2%), but with chromosome abnormalities or various malformations. CONCLUSION: The prognostic factors associated with a poor outcome are an abnormal karyotype and associated structural malformations. Resolution of the hygroma by 20 weeks gestation suggests a good prognosis, but is not definitive. All other factors evaluated do not appear to be of prognostic value at this time. Careful analysis of these prognostic factors is very important to identify the small percentage of normal children and to advise parents effectively for a future pregnancy.
OBJECTIVE: To develop an algorithm for the prenatal management of patients when a cystic hygroma is diagnosed by ultrasonography. METHODS: We report a personal series of 25 cases diagnosed between 10 and 23 weeks gestation and a review of the literature comprising a total of 999 cases. We focused on the etiologies and the value of various prognostic factors in the management of cystic hygromas. These include karyotype, alpha-fetoprotein levels, sonographic findings in the fetus and within the hygroma itself, and natural history. RESULTS: According to the literature, fetal chromosomal abnormalities were associated with cystic hygromas in 62% of the cases. Turner's syndrome remains the most common (33%) but Down's syndrome, Trisomy 18 and Trisomy 13 are not rare (15, 7 and 2%). Others have Mendelian abnormalities. The prognosis remains gloomy. The literature reports that only 9% of cases result in healthy children with normal karyotypes. The remaining 91% are either terminated (89%) or liveborn (2%), but with chromosome abnormalities or various malformations. CONCLUSION: The prognostic factors associated with a poor outcome are an abnormal karyotype and associated structural malformations. Resolution of the hygroma by 20 weeks gestation suggests a good prognosis, but is not definitive. All other factors evaluated do not appear to be of prognostic value at this time. Careful analysis of these prognostic factors is very important to identify the small percentage of normal children and to advise parents effectively for a future pregnancy.