Neural Tube
Defects
Epidemiology and
Etiology:
·
Anencephaly:
o 1-5 / 1000 live births
o F > M
·
Unknown etiology
·
Folate deficiency is a risk factor
Common sites:
·
Gross features:
·
Spina bifida (spinal dysraphism)
o Asymptomatic bony defect or a severe malformation with a
flattened, disorganized segment of spinal cord
·
Myelomeningocele
o Extension of
o Lumbosacral most common
·
Meningocele
o Malformation involving only bone, soft tissues, and meninges, no neural tissue
·
Anencephaly
o Absence of brain and calvarium
·
Posterior fossa structures may be spared
o Area cerebrovasculosa in its
place
·
Encephalocele
o Diverticulum of malformed
o Occipital or posterior fossa
most common
Histologic
features:
·
Meningocele:
o Meningothelial cells
o Loose fibrovascular connective
tissue
o Peripheral nerve twigs maybe
o Spinal nerve roots maybe
o Smooth muscle bundles maybe
o Dendritic melanocytes maybe
o Nodules of mature adipose tissue maybe (lipomeningocele)
·
Myelomeningocele:
o As meningocele but also contains
neuroglial tissue
·
anencephaly:
o area cerebrovasculosa:
·
remnant of
disorganized brain tissue with admixed ependyma, chroid plexus, and meningothelial
cells
Immunophenotype:
Marker: |
Sensitivity: |
Specificity: |
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Molecular features:
Other features:
·
serum elevated
alpha-fetoprotein (
o
·
clinical features:
o cord dysfunction if cord is disorganized
·
complications:
o infection through thin overlying skin (or defect)
·
counseling:
o recurrence risk 4-5% (but depends on underlying population
incidence)
References: