Hippocampal malrotation with normal corpus callosum: a new entity?

Area of Science:

• Neuroimaging
• Developmental Neuroscience
• Epilepsy Research

Background:

• Epilepsy is a neurological disorder characterized by recurrent seizures.
• Magnetic Resonance Imaging (MRI) is crucial for identifying structural brain abnormalities.
• Hippocampal malrotation (HIMAL) is a rare congenital brain malformation.

Purpose of the Study:

• To identify and characterize hippocampal malrotation (HIMAL) in patients with suspected epilepsy.
• To explore the association between HIMAL and other developmental disorders.
• To understand the potential role of HIMAL in the context of epilepsy and brain development.

Main Methods:

• Retrospective analysis of 527 MRI examinations in patients with suspected epilepsy over 5 years.
• Identification of 32 cases exhibiting characteristic features of HIMAL.
• Review of clinical features, associated developmental disorders, and family history.

Main Results:

• Hippocampal malrotation (HIMAL) was identified in 32 (6%) of 527 epilepsy patients.
• Characteristic MRI findings include incomplete inversion, round shape, abnormal collateral sulcus, and specific temporal horn enlargement.
• HIMAL was associated with developmental disorders in 22% of cases, predominantly in males, and often had a positive family history.

Conclusions:

• Hippocampal malrotation (HIMAL) may represent a mild hemisphere developmental disorder.
• HIMAL is likely a marker of underlying developmental abnormalities rather than the primary cause of epilepsy.
• Identifying HIMAL can aid in selecting patients for further investigation and contribute to understanding brain development.