A developmental classification of malformations of the brainstem

Area of Science:

• Neuroscience
• Developmental Biology
• Medical Imaging

Background:

• Advances in neuroimaging and genetics have led to increased identification of brainstem malformations.
• Brainstem anomalies present a complex diagnostic challenge for clinicians.

Purpose of the Study:

• To describe and classify brainstem anomalies in a cohort of 138 patients.
• To develop a classification system for brainstem malformations based on embryological mechanisms.

Main Methods:

• Retrospective review of magnetic resonance imaging (MRI) studies and clinical records from 138 patients.
• Segregation of malformations based on MRI findings and classification by embryological mechanisms.

Main Results:

• The pons was the most frequently affected region (114 patients), followed by the midbrain (45) and medulla (14).
• Fifty-three patients had anomalies in multiple brainstem regions.
• Malformations were categorized into four groups: abnormal segmentation, segmental hypoplasia, postsegmentation defects, and those associated with abnormal cortical organization.

Conclusions:

• Brainstem malformations are diverse and complex, necessitating a structured classification system.
• The proposed classification, based on embryological events, aids in understanding these disorders.
• This system can improve clinical diagnosis and family counseling for affected individuals.