Subependymal Gray Matter Heterotopia With Seizure in a 6‐Month‐Old Child

ABSTRACT

A 6‐month‐old male presented with seizures. Non‐contrast CT revealed subependymal gray matter heterotopia, corpus callosum dysgenesis, colpocephaly, and suspicious closed‐lip bilateral parieto‐occipital schizencephaly. Benign posterior fossa and subarachnoid space enlargement were noted. This case highlights the diagnostic value of imaging in rare neuronal migration disorders and associated structural abnormalities.

1. Clinical Question

A 6‐month‐old male infant presents with recurrent seizures for 1 week. Neurological examination reveals no significant focal deficits. A non‐contrast CT of the brain is performed. Based on the imaging findings (Figures 1, 2, 3, 4, 5), what is the most likely diagnosis, and how does it relate to the clinical presentation?

FIGURE 1.

Axial CT brain image showing subependymal calcifications along the ventricular surface, consistent with subependymal nodular heterotopia.

FIGURE 2.

Axial CT brain image showing prominent dilatation in the posterior fossa.

FIGURE 3.

Axial CT brain image demonstrating marked ventricular enlargement consistent with hydrocephalus, with evidence of cortical thinning.

FIGURE 4.

Axial CT brain image demonstrating marked ventricular enlargement of the retrocerebellar and supracerebellar areas.

FIGURE 5.

The axial CT image shows asymmetric dilation of the lateral ventricles with thinning of the corpus callosum.

2. Case

The CT scan reveals nodular gray matter along the lateral ventricular walls, characteristic of subependymal gray matter heterotopia (SGMH). Additional findings include corpus callosum dysgenesis, colpocephaly, and possible closed‐lip bilateral parieto‐occipital schizencephaly, with benign enlargement of the posterior fossa and subarachnoid spaces.

SGMH is a neuronal migration disorder in which gray matter fails to reach its normal cortical destination during embryogenesis, leading to ectopic nodules along the ventricular surface [1]. It is often associated with seizure, as seen in this case, due to the presence of abnormal cortical organization that predisposes to epileptiform activity [1]. The co‐occurrence of corpus callosum dysgenesis and colpocephaly further supports a developmental migration disorder. Beyond seizures, neuronal migration disorders can significantly impact neurodevelopment. Affected children may experience delayed motor milestones, intellectual disabilities, and cognitive impairments, depending on the severity and extent of the heterotopia. Early neuroimaging, even before the onset of seizures, can help diagnose these disorders in infants showing signs of developmental delay. Identifying these conditions early allows for proactive management, including early intervention programs, developmental therapies, and genetic counseling to optimize long‐term outcomes.

Imaging plays a critical role in diagnosis. CT is an important modality for diagnosis which reveals ectopic gray matter in various locations. Interestingly, this case also showed features suspicious for closed‐lip bilateral parieto‐occipital schizencephaly, a structural anomaly characterized by abnormal clefts in the cerebral hemispheres. While schizencephaly and SGMH are distinct conditions, their coexistence has been reported in the literature, likely reflecting a shared disruption in neuronal migration and cortical organization during fetal development. Management focuses on seizure control with antiepileptic therapy, developmental monitoring, and genetic counseling when a syndromic association is suspected [2]. Understanding such neurodevelopmental conditions is essential for early diagnosis and intervention, improving long‐term outcomes. In this case as well, the patient was managed on antiepileptic therapy and was monitored for developmental milestones.

Author Contributions

Bibek Shrestha: conceptualization, data curation, formal analysis, methodology, writing – original draft, writing – review and editing. Priyesh Shrestha: investigation, supervision, validation. Vivek Karn: investigation, supervision, validation. Shiva Ram Ale Magar: investigation, supervision, validation.

Disclosure

The authors have nothing to report.

Ethics Statement

The institutional review board (IRB) of the Institute of Medicine, Maharajgunj Medical Campus does not mandate ethical approval for the Case Image.

Consent

Written informed consent was obtained from the parents of the patient for publication of this case image and accompanying images, complying with the requirements as mentioned in Wiley's CCR Consent Form.

Conflicts of Interest

The authors declare no conflicts of interest.

Data Availability Statement

The authors have nothing to report.