Figure 3

Spinal cord and syrinx pathology in OEIS. A OEIS in a midgestation fetus with large dorsal myelocystocele (arrowhead). B Longitudinal section of caudal spine and myelocystocele in a near term infant with OEIS. The dorsal sac (asterix) is lined by ependyma and continuous with the central canal of the spinal cord (arrow) which herniates dorsally. The dorsal elements of the neural canal are absent in the midline below the upper lumbar spine (arrowhead) and the conus is low lying. C Same specimen as (A), whole mounted axial section of spinal column at the point where the cord herniates through dorsally between the separated spinal laminae (arrowheads). The central canal (asterix) is dilated and irregular with a discontinuous lining. D Axial section of cervical spinal cord of same specimen as (A) demonstrating dorsal syrinx with lateral extensions separate from a mildly dilated central canal (immunohistochemistry for vimentin). E Transverse section through the cervical cord of the same fetus as (B), demonstrating an irregular dorsolateral cavity with adjacent increased staining for alpha beta crystallin (arrowheads), separate from normal sized central canal (asterix). F Same specimen and level as (E), stained for myelin basic protein, with near total loss of myelin staining adjacent to the syrinx cavity.