Central nervous system pathology in the amniotic rupture sequence

We delineate and review the central nervous system (CNS) pathology of amniotic rupture sequence (ARS) and its extraneural associations.

We review a consecutive 15-year fetal/neonatal autopsy series for cases of ARS to document its morphology and correlates.

We retrieved 15 cases of ARS with complete dissection of the CNS. Seven lacked craniofacial abnormalities; in these the brain and spinal cord were normal. Eight had acalvaria or encephalocele, with facial clefts. All 8 had abnormal brains. Two cases demonstrated normal cerebral lobation with aqueductal stenosis/atresia (AS) and secondary changes. Two cases demonstrated holoprosencephaly and AS. Four other cases had large encephaloceles covered by amnion and extensive secondary change, 3 of which had absent olfactory bulbs, folded and thinned cerebral cortex, reduced thalami, and irregular ventricular systems with superimposed gliosis and hemorrhage. In these, the aqueduct or rostral 4^th ventricle was either atretic or occluded by heterotopic neuronal masses.

CNS pathology in ARS is strongly associated with craniofacial clefts. There is a non-random association between AS, holoprosencephaly, and ARS. Some of the anomalies may be due to abnormal induction events, vascular instability, and the mechanical effects of craniofacial maldevelopment.