Cephalocele detection in utero: sonographic and clinical features.

Sonographic and clinical features of 26 fetal cephaloceles were reviewed retrospectively. The most frequent reason for referral was elevated maternal serum alpha-fetoprotein levels. The smallest lesion identified was 0.4 x 0.5 cm (frontal, at 20 weeks); the largest was 9.0 x 10.0 cm (frontal, at 27 weeks). Twenty-four of 26 cephaloceles were detected on prenatal ultrasound examination; in 13 of these, more than 50% of the intracranial contents were exteriorized. Fifteen of 24 cephaloceles detected prenatally had a sulcal pattern (identified between 16 and 36 weeks' gestation); five were solid without a sulcal pattern (identified between 13 and 21 weeks' gestation), three were cystic, and one underwent a change in appearance from solid at 21 weeks to cystic at 26 weeks. Other cranial features were evaluated and included visible skull defect, seen in 23/24 (96%), ventriculomegaly, in 6/26 (23%); microcephaly, in 12/24 (50%); beaked tectal plate, in 6/16 (38%); and flattened basiocciput, in 9/24 (38%). Of the 26 cases, 14 had normal amniotic fluid volume, five had oligohydramnios and seven had polyhydramnios. Fetuses with oligohydramnios had the highest incidence of concurrent fetal abnormalities; four of five fetuses (80%) with oligohydramnios had additional structural abnormalities. In the overall population, a very high incidence of other abnormalities was found; 17/26 (65%) cases showed additional abnormalities, some of which were not detected by ultrasound. Five fetuses had Meckel-Gruber syndrome and three had amniotic band syndrome. Only one of the 18 karyotypes obtained was abnormal (trisomy 18). Survival was very poor; only two of the eight who survived until birth are currently living.