A rare case of schizencephaly in an adult with late presentation.

Schizencephaly, i.e., split brain, is a rare, congenital cerebral malformation. Magnetic resonance imaging is the best neuroimaging modality for its diagnosis. In literature, only few cases have been reported causing symptoms in adults. Symptomatic patients present as hemiparesis, developmental deficits to seizures. This condition is usually found at birth and presents during early years. Appropriate diagnosis of the disease is necessary to avoid incorrect treatment. Here, we present a rare case of left, unilateral, open lip schizencephaly in an adult patient presenting with partial seizures but with an asymptomatic childhood.

Introduction

Schizencephaly is an uncommon, congenital disorder showing developmental cerebral malformation characterized by clefts in the cerebral cortex, which extends from the ependymal surface of the ventricle through the white matter to the pial surface. Magnetic resonance was more sensitive than computed tomography in detecting the clefts.[1] Yakovlev and Wadsworth first coined the term “schizencephaly” in 1946, in their study on cadavers.[2] Schizencephaly is associated in some cases with microcephaly, hydrocephalus, or other malformations such as septo-optic dysplasia.[13] This disorder can be detected in vivo by ultrasonography.[4]

A prevalence of schizencephaly of 1.54 in 100,000 was reported in a population-based study in the United States.[5] Worldwide incidence of this rare congenital malformation is approximately 1.5 in 1,000,000 live births and 1:1650 among children suffering from epilepsy. However, schizencephaly as a cause of seizure in an adult is very rare. No clear-cut gender predilection is noted, but in a study by Stopa et al., they found a slight male preponderance and magnetic resonance imaging (MRI) as an investigation of choice to diagnose schizencephaly and associated anomalies.[6] A study done by Howe et al.[7] found the condition to be more frequent in infants born to younger mothers and is familiar. Various hypotheses have been suggested. It is believed to be because of abnormal neuronal migration or due to localized ischemia. Other causes are the expression of genetic factors such as the mutant gene, EMX2. These expressed genetic factors are believed to damage the periventricular germinal matrix impairing the cellular migration at 6–7 weeks of the intrauterine growth.[7] Sarnat and Curatolo, in their research, described this as an extreme form of true porencephaly due to the ischemic theory. The exact cause of this disorder is still not known.[8]

Case Report

A 48-year-old male patient was referred to the Radiodiagnosis Department for MRI brain in view of history of recurrent (three episodes) partial seizures for the last 6 months. He had a history of right-sided headache for the past 2 years which relieved after taking oral medications. However, even after medication, the patient complained of lack of activeness and partial weakness on the right side since then. He was symptomatically on the anticonvulsant sodium valproate. There was no history of any episode of seizures in the past apart from seizure episode before 6 months. Family history and birth history were insignificant. The patient then was asked about his birth history which was found normal. His mother had no complications during pregnancy. There were no postnatal complications. There was no global delay in the developmental milestones. Vital signs were normal. In detail, blood and other laboratory investigations were done to rule out metabolic and other causes of seizure.

MRI brain study showed a wide cerebrospinal fluid (CSF)-filled gray matter lined cleft that extends through the cerebral hemisphere on the left side [Figures 1–3]. The cleft extended from the ependyma of left lateral ventricle to the subarachnoid space of left parietal region. Communication of the subarachnoid space with the left lateral ventricle medially with infolding of the gray matter along the cleft was noted.

Figure 1

Magnetic resonance, T2- and T1-weighted images, axial section (yellow arrow) showing the cerebrospinal fluid-filled cleft and lined by the cortical gray matter that is extending from the subarachnoid space of the left parietal lobe region communicating with the left lateral ventricle

Figure 3

Magnetic resonance, T1-weighted image, coronal section, arrow showing the cerebrospinal fluid-filled cleft and lined by the cortical gray matter extending from the subarachnoid space of the left parietal lobe region communicating with the left lateral ventricle

Magnetic resonance, T2-weighted images, sagittal section, arrow showing the cerebrospinal fluid-filled cleft and lined by the cortical gray matter extending from the subarachnoid space of the left parietal lobe region communicating with the left lateral ventricle

Right lateral ventricle was normal. Septum pellucidum noted was normal. There was no evidence of hydrocephalus. Corpus callosum appeared normal. Right cerebral hemisphere, cerebellum, pons, and midbrain were found to be normal. A diagnosis of left open lip schizencephaly was made as communication of the left lateral ventricular system with subarachnoid space of left parietal region was noted. The patient was explained about the disease and advised to continue the medical management of sodium valproate.

Discussion

Schizencephaly is gray matter lined cerebrospinal-filled clefts that extend from the ependymal surface to the pial membrane. There are two types reported, Type I or closed lip and Type II or open lip where the walls are separated from each other and filled with CSF. Type II is more common than Type I with 60% of unilateral schizencephaly being open type.

The clefts can be bilateral or unilateral, symmetrical or asymmetrical and can occur anywhere in the brain. It is, however, more common in the parietal and frontal lobes.[1] Our patient has presented with Type II left unilateral schizencephaly, with the walls of the right parietal lobe cleft being widely separated from each other and not lined by polymicrogyric gray matter and having normal intelligence.

Schizencephaly is frequently associated with other congenital abnormalities in 50%–90% of cases such as agenesis of the septum pellucidum and corpus callosum, polymicrogyria-pachygyria (unusually thick convolutions of the cerebral cortex), heterotopias (ectopic gray matter), septo-optic dysplasia, and optic nerve hypoplasia. Our patient was not found with any other associated congenital abnormalities. Presentation and outcome are variable with the severity of symptoms depending on the amount of brain tissue affected. Common presenting features are seizures, hemiparesis mental retardation, delayed milestones, and motor defects. This patient presented with seizures and weakness of the right side but completely normal developmental milestones and normal childhood. Our case is unusual as very few cases (exact number not mentioned in literature) are reported who have absolutely normal life till (fourth decade) their adulthood,[910] and showed symptoms at such later stage of life.

MRI gives excellent demonstration of the anatomic changes and visualization of the gray matter which lines the clefts and it is pathognomonic of schizencephaly differentiating it from porencephaly as well as in identifying other acquired and associated lesions.

This left-sided open lip schizencephaly is the most likely cause of seizure in our patient as other causes of seizure were ruled out clinicopathologically as well as radiologically.

Both types of schizencephaly can be managed conservatively. It predominantly consists of rehabilitation of symptoms such as motor defects and mental retardation and control of seizures. Differential diagnosis of this defect includes focal cortical dysplasia, porencephaly, and band of heterotopic gray matter. Schizencephaly, although a rare congenital disorder, can occur in our environment and can be found even in adult population causing symptoms.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.