Dandy-Walker malformations

Pathogenesis

• Congenital anomaly thought to arise from abnormal development of the rhombencephalon
• Result in abnormal expansion of the forth ventricle
• Prevent normal caudal migration of the tentorium and torcular herophili

Key features

• Marked vermian hypoplasia/agenesis
• Cystic dilatation of the fourth ventricle
• Torcular-lambdoid inversion
  (Torcular lies too far superiorly, cranial to the lambdoid suture)

Association

• CNS
  • Grey matter heterotopias
  • Cortical dysplasias
  • Callosal dysgenesis
• Non-CNS
  • Cleft lip and palate
  • PHACES syndrome
  • Cardiac malformations
  • Genitourinary abnormalities