HYDRANENCEPHALY
PORENCEPHALY
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Partial or subtotal defects in cerebral hemispheres due to ischemia,
hemorrhage infection or tumor (1). Occurs between the second trimester and
early post natal period.
- Single unilateral cavity within
the cerebral hemisphere.
- May / may not communicate
with the ventricles.
- Ultrasound.
- Cystic lesion that
communicates with the ventricle.
- Dilatation of the
ipsilateral ventricle.
- No mass effect
(differentiates it from an arachnoid and interhemispheric cyst).
- Massive bilateral lesions.
- Most of the cerebral hemispheres
are a fluid filled CSF sac.
- Thought to be due to ICA
occlusion (similar cerebral lesions have been produced in monkeys by
ligating both carotid arteries (2).
- Several reports of in utero
development of hydranencephaly resulting from intracranial hemorrhage
(3,4).
- Normal size skull or macrocephaly.
Skull normally formed.
- Fluid filled cranial
cavity.
- No cerebral cortex (may
have partial preservation of the occipital lobe).
- Falx intact and
usually present.
- Midbrain and basal
ganglia are normal.
- Thalami normal and
never fused (3).
- Cerebellum intact with
a normal tentorium cerebelli (3).
- Polyhydramnios.
- The earliest reported
diagnosis was made at 12 weeks of gestation (4).
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No cerebral cortex; Falx intact and usually present
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- Massive hydrocephalus (all
parts of the ventricular system dilated).
- Alobar
holoprosencephaly (thalami fused and no falx present)
- Volpe JJ. Hypoxic-ischemic
encephalopathy, neuropathology, and pathogenesis. In: Neurology of the
newborn: Neuronal proliferation, migration, organization and myelination.
Philadelphia, WB Saunders;1995:299-307.
- Myers RE. Brain pathology
following fetal vascular occlusion: an experimental study. Invest
Opthalmol 1969;8:41-50.
- Greene MF, Benacerraf B,
Crawford JM. Hydranencephaly: Ultrasound appearance during in utero
evolution. Radiology 1985;156:779-780.
- Lin YS, Chang FM, Liu CH. Antenatal
detection of Hydranencephaly at 12 weeks menstrual age. J Clin Ultrasound
1992;20:62-64.
- Edmondson SR, Hallak M,
Carpenter RJ et.al. Evolution of hydranencephaly following intracerebral
hemorrhage. Obstet Gynecol 1992;79:870-871.