Prenatal diagnosis of acrania associated with amniotic band syndrome

The amniotic band syndrome is a collection of fetal malformations associated with fibrous bands that appear to entrap or entangle various fetal parts in utero and can affect any organ or system and cause a single or multiple anomalies. The anomaly, acrania, is characterized by partial or complete absence of the calvarium with abnormal brain tissue development. Literature reports association of amniotic band syndrome and acrania postnatally, but not diagnosed prenatally by ultrasound.

A young woman, gravida 1, para 0, presented for an initial prenatal visit at 35 weeks' gestation and had a first ultrasound that showed a single intrauterine pregnancy at 36 weeks' gestation. This ultrasound also showed polyhydramnios, absence of or a very small cerebrum with either anencephaly or acrania. A targeted ultrasound scan was performed on the following day, which confirmed acrania in view of the fact that we did see an absence of the flat bones of the skull with a substantial amount of abnormal brain tissue present surrounded by a fetal membrane. The patient was counseled, and labor induction was scheduled with a male infant delivered weighing 1763 g after a spontaneous vaginal delivery. The infant was diagnosed with acrania, given supportive care, and died 11 hours later.

Diagnosis of cranial bone defects can be established by ultrasound in the first trimester of pregnancy. The prenatal diagnosis of acrania associated with amniotic bands by transvaginal ultrasound was visualized in the third trimester in this case; therefore, appropriate counseling and treatment options were offered.