Imaging
Findings
Study shows a cleft in the temporal lobe, communicating with a prominent
extra-axial space with temporal lobe atrophy.
Diagnosis
Schizencephaly (open type)
Discussion
Clinical Findings
Patients may present with seizure disorders, mild to moderate
developmental delay and mental retardation.
Etiology/Pathophysiology
Failure of the normal migration of neurons from the germinal matrix zone
at 1-5 months of gestation. A gray matter lined parenchymal cleft develops
which extends from the subarachnoid space to the subependyma of the
lateral ventricles. Schizencephaly occurs when there is a failure of the
normal migration of neurons from the germinal matrix zone at 1-5 months of
gestation. Some theories suggest that possible causes of this are in-utero
stroke, early gestational viral infections, and recent Italian research
has linked Schizencephaly with a mutated gene called the Homeobox gene
EMX-2. If the gene EMX-2 is missing or defective, nerve cell growth and
migration will not occur normally and this
will lead to the formation of the 'clefts' associated with Schizencephaly.
The
cleft may be narrow or closed (type 1) or wide and open (type 2). It is
frequently associated with complete or partial absence of the cavum septum
pellucidum in approximately 80-90% of cases. the cleft is usually located
near the pre- or postcentral gyri. The clefts can be unilateral or
bilateral. Polymicrogyria, microcephaly, and gray matter heterotopia have
also been noted. Optic nerve hypoplasia has been noted in 33% of cases,
with possibility of blindness.
Differential
Diagnosis
Pseudoporencephaly
due to trauma, vascular, or infectious insults, which are almost always
unilateral.
Cystic tumor
Arachnoid cyst
References
1.
Behrman RE, Kliegman R. Nelson Essentials of Pediatrics. Philadelphia, W.B.
Sander, 1990 pg. 651-652.
2. Blickman J.G. Pediatric Radiology, The Requisites. ST Louis, Mosby,
1994. pg 210.
Site For
Parents of Kids with schizencephaly:
http://www.geocities.com/Heartland/Meadows/7384/
Contribution
Dr.
Sanjeev Mani, Mumbai
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