





















































Schizencephaly A case report


Schizencephaly – A case report

P. K. Chhetri1, S. Raut2

1Assistant Professor, 2Junior Resident, Department of Radiodiagnosis, College of Medical Sciences, Bharatpur, Chitwan

district, Nepal

Abstract

Schizencephaly is an uncommon congenital cerebral malformation that involves the cerebral mantle

and consists of a cleft that extends through the entire cerebral hemisphere from the lateral ventricle to

cerebral cortex. The condition is present at birth and present early in life. Here we present an adult

patient with schizencephaly presenting with first onset seizure.

Key words:  schizencephaly, lateral ventricle,seizure imaging diagnosis

Introduction

Schizencephaly (split brain) is a gray matter-lined

cerebrospinal fluid – filled cleft that extends from the

ependymal surface of the brain through the white matter

to the pia. There is no well-documented data on its

incidence.1 Two types are recognized, which have

prognostic significance. In type I or closed-lip

schizencephaly, the cleft walls are in apposition and

type II or open lip schizencephaly, in which the walls

are separated. Schizencephaly type II occurs more

commonly than type I.1

In either instance the cleft is lined by heterotopic gray

matter. In most cases, the gray matter along the cleft is

polymicrogyric; in some instances, it is more dysplastic

than polymicrogyric. 2 The clefts can be unilateral or

bilateral, symmetric or asymmetric and can appear

anywhere in the brain, although they usually are

perisylvian. In unilateral cases, perusal of the

contralateral hemisphere is warranted, as subtle clefts

of polymicrogyria are common.2

Case Report

A 50 year old male patient was referred for CT

scan of the head for a single episode of a generalized

tonic - clonic seizure. Apart from mental retardation

present since birth no other significant history could be

elicited. A non - contrast enhanced CT scan of the

head was performed. Axial (Figure 1) and coronal

(Figure 2) CT scan shows the wide open - lip

schizencephaly with communication of the left lateral

ventricle and the subarachnoid space on the left side.

There is also absent septum pellucidum and partial

thinning of the skull vault on the left side (temporo-

parietal region).

Figure 1 Figure 2
Correspondence: Dr. P K Chhetri

E-mail:pramodchhetri@rediffmail.com

Case Report, 54-56Journal of College of Medical Sciences-Nepal, 2010, Vol. 6, No. 1

54



Discussion

Several theories have been proposed to explain

the etiology of schizencephaly, although none is

universally accepted. However, an ischemic episode

occurring at the 7 th week of gestation has been

hypothesized as an etiological factor. In the normal

embryo, beginning7 th week of gestation, neuroblasts

are generated in the germinal matrix. During the 8 th

week these primitive cells begin to migrate along radially

oriented glial cells to the cerebral cortical regions.

During that critical period, any insult to the centripetal

and centrifugal vessels in the region of germinal matrix

may cause hypoxaemia and infarction with arrest of

migration of these neuroblasts.3 Conversely, another

author favours a primary developmental abnormality

to account for the combination of schizencephaly and

absence of the cavum septum pellucidum.4 Recently,

mutations in the homebox gene, Emx2 located on

chromosome 10q2.6, have been reported in some

patients with schizencephaly.2

Presenting symptoms relate to the amount of

involved brain. Children with closed-lip schizencephaly

typically present with hemiparesis or motor delay,

whereas patients with open-lip schizencephaly usually

present with hydrocephalus or seizures. Patient with

closed-lip schizencephaly are more likely to have mild

to moderate neurologic deficit than those with open-

lip type. Unilateral closed-lip schizencephaly is

associated with the best neurodevelopmental outcome.

Patients with progressively larger clefts present with

progressively greater neurologic deficits because

progressively more brain is missing. Nearly all patients

with bilateral open-lip clefts have severe disabilities. 2

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 pial-

ependymal seam, may be difficult to detect on CT

scans but is easily discernible on MR studies. Open-

lip schizencephaly has a larger, more apparent gray

matter-lined CSF cleft. 5

CT may show subependymal or parenchymal

calcification in many cases, which suggests that one

cause of schizencephaly may be intrauterine infection

with cytomegalovirus. 6

MRI is the imaging modality of choice because of

its superior differentiation of gray matter and white

matter and its ability to image in more than one plane.

Identification of gray matter lining the cleft is the

pathognomic finding. 1

MRI shows the abnormal appearance of the cortical

mantle along the cleft and the cortex appearing thicker

than normal owing to the presence of polymicrogyria.

The contralateral hemisphere may also have

developmental abnormalities, such as polymicrogyria

and subependymal heterotopias. 6

Mild hypoplasia of the corpus callosum is

commonly seen. The septum pellucidum is absent or

nearly completely absent in 70% to 90% of affected

patients. Of those with absence of the septum

pellucidum, 30-50 % will have optic nerve hypoplasia

on clinical examination. Therefore, septo-optic

dysplasia is, by definition, present in 20-45% of patients

with schizencephaly.2 Optic atrophy is usually easily

recognizable clinically but is often difficult to confirm

on imaging.

In addition to the brain anomalies, in patients with open-

lip schizencephaly, CSF pulsations from the lateral

ventricles result in pressure effects on the inner table

of the skull.2

P. K. Chhetri et al. Schizencephaly – A case report

55



References
1. Bird CR, Gilles FH. Type 1 schizencephaly: CT and

neuropathologic findings. Am J of Neuroradio 1987;Vol

8,(3):451-4

2. Robertson R, Caruso PA, Truwit CL et al Disorders of

Brain Development. In: Magnetic Resonance Imaging

of the Brain and Spine. Scott W. Atlas. 3 rd Edition.

Lippincott Williams & Wilkins, 2002;356-60

3. Chuang SH, Fitz CR, Chilton SJ et al: Schizencephaly;

Spectrum of CT findings in association with septo-optic

dysplasia. Presented at the 70 th Scientific assembly

and annual meeting of Radiological Society of North

America Washington DC November. Radiology

1984;153:118

4. Page LK, Brown SB, Gargano FP et al. Schizencephaly:

a clinical study for review. Child Brain 1975;1:348-58

5. Anne G. Osborn. Disorders of Diverticulation and

Cleavage, Sulcation and Cellular Migraton. In:

Diagnostic Neuroradiology. Mosby, 1994;52-4

6. Gunny RS,  Chong WKK. Paediatric Neuroradiology.

In: Grainger & Allison`s Diagnostic Radiology. 5 th

Edition. Volume II. Churchill Livingstone Elsevier,

2008;1660

Journal of College of Medical Sciences-Nepal, 2010, Vol. 6, No. 1

56


