Bilateral giant open-lip schizencephaly: A rare case report.

Schizencephaly is an extremely rare developmental birth defect characterized by abnormal slits or clefts in the cerebral hemispheres extending from the lateral ventricle to the cerebral cortex. The margins of the cleft are lined with heterotropic, dysplastic gray matter. The causes of schizencephaly are heterogeneous and include teratogens, prenatal infarction/infections, maternal trauma, or EMX2 mutations. This condition is present at birth and manifests early in life.

Introduction

Schizencephaly (split brain) is a gray matter-lined cerebrospinal fluid (CSF)-filled cleft extending from the ependyma to the pia mater. Schizencephaly is a rare disorder with an estimated incidence of 1.5:100,000 live births in the United States. It is almost always sporadic although a few familial cases have been described. There is no known gender predilection.[1]

Schizencephaly can sometimes be bilateral and is divided into two morphological types:

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. Schizencephaly Type II occurs more commonly than that of Type I.[2]

Herein, we report a rare case of bilateral giant open-lip schizencephaly.

Case Report

A 15-day-old female child was referred to neurosurgery department with enlarged head and poor breastfeeding since birth. There was history of seizures and patient was on antiepileptic drugs. Antenatal history was uneventful. Family history was not significant. On examination, macrocephaly with tense fontanelles was present. Scalp was thin and shiny with visible veins. Central nervous system examination revealed spasticity of left upper and lower limbs with brisk deep tendon reflexes. The power in the left upper and lower limb was 4/5. In view of patients, clinical symptomatology radiological investigations were performed. Computerized tomography brain showed large fluid density lesion in both frontoparietal lobes with thinning of brain parenchyma [Figure 1]. The lesion appeared to be communicating with lateral ventricle. Magnetic resonance imaging (MRI) brain revealed a large CSF attenuation gray matter-lined cleft present in both fronto- and temporo-parietal region extending from pial surface to ependymal lining of the lateral ventricles. Associated anomalies were partial agenesis of the corpus callosum and absence of septum pellucidum [Figures 2 and 3]. Based on clinical and radiological features, diagnosis of schizencephaly was made.

Figure 1

Computerized tomography brain showing large fluid density lesion in both fronto- and temporo-parietal lobe with thinning of brain parenchyma

Figure 2

Magnetic resonance imaging brain axial section showing large cerebrospinal fluid attenuation gray matter-lined cleft present in both fronto- and temporo-parietal region

Figure 3

Magnetic resonance imaging brain sagittal and coronal section showing bilateral large schizencephaly with partial agenesis of the corpus callosum and absence of septum pellucidum

In view of hydrocephalus, the patient was subjected to surgery. Ventriculoperitoneal (VP) shunt was performed. Muscle relaxants and physiotherapy were started for spasticity. The child showed improvement during follow-up.

Discussion

Schizencephaly is a rare cortical malformation that manifests as a gray matter-lined cleft extending from the ependyma to the pia mater. In 1946, Yakovlev and Wadsworth first described schizencephaly as hemispheric clefts in the region of the primary fissures, infolding of gray matter along the clefts, and associated cerebral malformations. The schizencephaly clefts are mostly perisylvian or centrally located.[3]

Schizencephaly is of two types: Type I (closed-lip) schizencephaly is characterized by gray matter-lined lips that are in contact with each other and Type II (open-lip) schizencephaly has separated lips and a cleft of CSF, extending to the underlying ventricle.[3] Our case is open-lip schizencephaly.

Exact pathogenesis is not known, but an ischemic episode occurring at the 7th or 8th week of gestation has been hypothesized as an etiological factor. At the 8th week of gestation, neuronal migration starts to form the cerebral cortex from the germinal matrix. These primitive cells begin to migrate along radially oriented glial cells to the cerebral cortical regions. During this period, any insult of vessels in the region of germinal matrix may cause hypoxemia and infarction with arrest of migration of these neuroblasts.[34] Other factors such as infection, metabolic disorders, and genetic defects also play an role in the development of schizencephaly. Granata T et al. have reported heterozygous mutations of the EMX2 gene associated with schizencephaly.[5]

Presenting symptoms are quite variable and related to the amount of brain parenchymal involvement. In general, patients presented with hemiparesis, seizures, and developmental deficits. The severity of manifestations depends on the size and location of the clefts. Patients may present in infancy, childhood, or adults. Patients with closed-lip schizencephaly typically present with hemiparesis and/or motor delay whereas patients with open-lip schizencephaly usually present with hydrocephalus and/or seizures. Patients with closed-lip schizencephaly are more likely to have mild to moderate neurologic deficit than those with open-lip type.[6] In our case, patient had hydrocephalus, seizures, and left hemiparesis.

Holoprosencephaly, arachnoid cyst, hydranencephaly, and porencephaly are included in the differential diagnosis of schizencephaly. Porencephaly also extends from the cortical surface to the ventricular surface but is lined by gliotic white matter, not gray matter. Some authors consider schizencephaly as true porencephaly.[6]

MRI is the investigation of choice because of its superior differentiation between gray matter and white matter. Identification of gray matter lining the cleft is the pathognomonic finding for schizencephaly. Other associated anomalies are mild hypoplasia of the corpus callosum (most common), absence of septum pellucidum, septo-optic dysplasia.[7] These findings were also present in our case.

As a rule, therapeutic management of both types of schizencephaly is conservative and predominantly consists of rehabilitation for motor deficits and mental retardation. These patients also need treatment for epilepsy. Surgical treatment is undertaken only in some cases with concomitant hydrocephaly or intracranial hypertension.[8] In view of hydrocephalus, our patient underwent a VP shunt.

Conclusion

Schizencephaly can be considered as a differential diagnosis in children who present with cystic lesions in brain and neurological deficit. An early surgical intervention may help in considerable improvement and limit disability in the child.

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Conflicts of interest

There are no conflicts of interest.