Presentations

Abstract

Introduction: Band heterotopia, also known as double cortex syndrome, is a type of malformation of cortical development in which neuronal migration is disrupted, leading to a band of gray matter situated between the ventricular and cortical surfaces of the brain. This band of gray matter disrupts normal brain architecture and leads to seizures, developmental delays, and in rare cases, hypotonia, and other neurologic deficits. The severity of symptoms is associated with the thickness of the gray matter band. Patients can present in early childhood or remain asymptomatic into their adolescent years. Magnetic resonance imaging (MRI) shows bilateral, symmetric band of gray matter within the cortical white matter pathognomonic for band heterotopia, making it the gold standard method of diagnosis for this condition. It is important to determine the need for MRI screening in patients with new onset recurrent seizures to evaluate for disruptions of cortical development, including band heterotopia, to accelerate proper care. Here we present the case of band heterotopia in a 37-year-old male.

Case Information: Clinical History: A 37-year-old male with a history of intractable epilepsy presented for evaluation. The patient's family history was non-contributory, and there was no history of perinatal complications. Imaging Findings: 1. Subcortical band heterotopia involving the bilateral frontal and parietal lobes. The overlying cortex appears normally formed, no pachygyria. 2. No other seizure focus identified. The hippocampi have a symmetric appearance, no mesial temporal lobe sclerosis or mass. 3. Small right mastoid effusion, nonspecific. These imaging findings are consistent with band heterotopia (double cortex syndrome), a form of lissencephaly spectrum disorder. The typical bilateral and symmetric bands of gray matter located in the subcortical white matter confirmed the diagnosis.

Discussion/Clinical Findings: Normal cortical development involves the migration of neurons from the ventricular zone to the cortical plate. The Doublecortin (DCX) protein is theorized to direct this neuronal migration, and mutations in the DCX gene cause some neurons to fail to reach the cortex. The neurons are arrested in the white matter rather than migrating to the cortical plate, resulting in the characteristic subcortical band of gray matter seen in MRI. Males with DCX mutations typically develop lissencephaly, while females often present with band heterotopia due to the X-linked inheritance pattern. Patients with band heterotopia typically present with seizures, ranging from mild to severe, and varying degrees of cognitive impairment. The severity of neurological symptoms often correlates with the thickness of the heterotopic band. In rare cases, symptoms may include hypotonia, developmental delays, and other neurologic deficits. The disorder can present as either a thin or thick band and may appear in a nodular or diffuse form. MRI is the diagnostic modality of choice, as it delineates the heterotopic gray matter from the surrounding white matter and cortical structures. The early diagnosis of band heterotopia through imaging is crucial for the effective management of seizures and for providing genetic counseling to affected families. Band heterotopia is frequently associated with other conditions within the lissencephaly spectrum. Management of patients includes regular MRI monitoring, neurologic evaluation, appropriate seizure medications, and referral for genetic counseling. Early intervention is essential for optimizing outcomes in patients with this disorder.

Conclusion: Band heterotopia is a rare neuronal migration disorder characterized by the presence of heterotopic gray matter in the subcortical white matter. This case highlights the importance of recognizing the characteristic MRI findings associated with band heterotopia, particularly in patients presenting with epilepsy. MRI is essential for confirming the diagnosis and differentiating band heterotopia from other cortical malformations. Early and accurate diagnosis via MRI allows for timely intervention, which is critical in managing seizures and associated symptoms. Effective management typically involves a multidisciplinary approach, including the integration of radiology for accurate diagnosis, neurology for seizure management, and genetic counseling for family planning. This comprehensive approach enhances patient care and optimizes long-term management and quality of life for individuals affected by this condition.