schizencephaly

SKSethi, RS SolankI
Ind J Radiol Imag 2004 14:1:95-96


SCHIZENCEPHALY

Schizencephaly is one of the migrational disorders of brain, which include lissencephaly, pachygyria, heterotopia, and polymicrogyria.it is characterized by a gray matter lined cleft that extends from the ependymal surface of the brain through the white matter to the pia.[1]
Two types are recognized: type I, or closed lip schizencephaly, in which the cleft walls are in apposition, and type II, or open lip schizencephaly, in which the walls are separated. In either instance the cleft is lined by heterotopic gray matter. The clefts can be unilateral or bilateral, symmetric or asymmetric.[2]
Bilateral clefts have a worse prognosis for development, with seizures present in the majority. Patients may present with hemiparesis (more likely in unilateral forms) or tetraparesis (more likely in bilateral forms). Mental retardation and seizures are other common presentations, being more severe in bilateral clefts.[3]
CT scans of closed lip schizencephaly may show only a slight outpouching, or "nipple" at the ependymal surface of the cleft. The full thickness cleft or the pial-ependymal seam may be difficult to detect on CT scans. Open lip schizencephaly has a larger, more apparent gray matter lined CSF cleft. The majority of patients have bilateral clefts, most of them roughly symmetrical in location and more likely open (type II) than closed (type I) the presence of heterotopic gray matter is considered pathognomic for schizencephaly, distinguishing it from an acquired condition. [4]

Reference
Barth PG. Schizencephaly and Nonlissencephalic Cortical dysplasias. AJNR 1992;13: 104-106.
Osborn AG. Disorders of Diverticulation and Cleavage, Sulcation and Cellular Migration. In Osborn AG's Diagnostic Neuroradiology : St. Louis, Mosby-Year Book Inc,1997;Chapter 3: 52-56.
Denis D, Chateil JF, Brun M et al. Schizencephaly: clinical and imaging features in 30 infantile cases. Brain & Development 2000;22: 475-483.
Sener RN, Bilgin G, Mermis A. CT of Schizencephaly. Am J Roentgenol 1992 Aug;159(2): 436