Radiology Resident Case of the Week
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.
Pathology:
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. Prognosis is poor, with severe intellectual impairment, spastic tetraplegia and blindness.
Miscellaneous
Most brain malformation can be produced by a variety of injuries during gestation. This includes infections, X-radiation, certain drugs, metabolic and genetic abnormalities.
Imaging
CT or MRI
DDX
1. Pseudoporencephaly due to trauma, vascular, or infectious insults, which are almost always unilateral.
2. Cystic tumor
3. Arachnoid cyst
Key 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.
3. Dahnert W. Radiology Review Manual 2nd ed. Baltimore, Williams and Wilkins . 1993. pg. 204.
ACR Code
132.1423
Keywords:
1. schizencephaly 2. clefts 3. brain malformations