Prenatal diagnosis of herniated Dandy-Walker cysts.
OBJECTIVE
The purpose of this series is to describe the prenatal diagnosis and pregnancy outcome of fetuses affected with Dandy-Walker malformation in which a posterior cyst herniated through a bony defect of the occipital skull, foramen magnum, or both.


METHODS
Two- and 3-dimensional sonography were used to examine 2 fetuses with poorly delineated cerebellar structures and a large posterior cystic neck mass. Fetal magnetic resonance imaging (MRI) was added to this evaluation as a complementary diagnostic modality.


RESULTS
Three-dimensional sonography helped characterize the precise site of cyst herniation through the occipital skull or foramen magnum. Fetal MRI confirmed the sonographic findings. Neonatal MRI studies identified heterotopic gray matter as evidence of a neuronal migration disorder in both fetuses. The second fetus also had agenesis of the corpus callosum. Retrospective review of the fetal MRI (25.9 weeks' menstrual age) and 3-dimensional sonographic (18.7 weeks' menstrual age) studies confirmed ventricular wall nodularity involving the occipital horns of the second fetus.


CONCLUSIONS
The antenatal detection of a large posterior cystic neck mass and a poorly defined or nonvisualized cerebellar vermis suggest Dandy-Walker malformation with a herniated cyst. Three-dimensional sonography and fetal MRI are important adjunctive methods that can be used to evaluate the herniation site and a possible neuronal migrational disorder.
Lee
Wesley
W
Division of Fetal Imaging, Department of Obstetrics and Gynecology, William Beaumont Hospital, Royal Oak, MI 48073-6769, USA. wlee@beaumont.edu
Vettraino
Ivana M
IM
Comstock
Christine H
CH
Lal
Nirish
N
Kazmierczak
Chris
C
Shetty
Anil
A
Raff
Gil
G
Zakalik
Karol
K
Romero
Roberto
R
D000328:Adult; D003616:Dandy-Walker Syndrome / Q000150:complications / Q000000981:diagnostic imaging*; D005260:Female; D005315:Fetal Diseases / Q000000981:diagnostic imaging*; D006257:Head / Q000000981:diagnostic imaging / Q000196:embryology; D006547:Hernia / Q000000981:diagnostic imaging* / Q000209:etiology; D006801:Humans; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging; D009333:Neck / Q000000981:diagnostic imaging / Q000196:embryology; D011247:Pregnancy; D016216:Ultrasonography, Prenatal