Brain and cranial disruption sequence from amniotic bands: a result of traction from fetal and embryonic swallowing of attached bands

Abstract

Ultrasonographic evaluation of a 16 week fetus referred for elevated MSAFP revealed multiple amniotic bands; the right digits were tethered to a ball of umbilical cord, in turn attached by a long band to the fetal surface of the amnion. Severe hydrocephaly was present, remarkable this early in gestation. The appearance of the choroid plexes was highly unusual, as if compressed focally, with a “butterfly” appearance in the coronal plane. A disruptive cleft extended from the right orbit through the right lateral maxilla and upper lip. Because of the poor prognosis, the patient elected to terminate the pregnancy. Chromosomal analysis revealed a normal karyotype. 3 dimensional computed tomography of the fetus skull revealed irregular synostosis of the right lambdoidal and right coronal sutures, with abnormal widening of the contralateral sutures. The fetal skin over the cranium was remarkable for the presence of three skin tags. The terminal phalanges of the right hand were disrupted by the band, which attached to the cord and amnion. Fetal surgery has demonstrated how the skin can regenerate without scarring. The cranial skin showed no evidence of scarring, but what most likely happened is that the fetus swallowed the bands attached at the 3 points on the cranium marked by the skin tags, and traction caused the bands to slice down through the cranium and brain structures, disrupting the choroid, brain anatomy, and causing the asymmetric craniostenosis and facial cleft. The skin over the cranium then healed over the defect without scarring. Also presented is a neonate with focal disruption of the toes, most likely caused by a band originally attached to the lateral surface of that foot's heel, leaving only a large skin tag as evidence of the original attachment. Other fetuses are shown with an amniotic band swallowed. The caveat: whenever amniotic bands are seen, meticulous evaluation of brain structures is warranted, and asymmetry of the choroid could be an ominous sign of more severe disruption.