DandyWalkerMalformation

Dandy-Walker malformation is a congenital brain malformation that affects the cerebellum and the fourth ventricle. The classic form is characterized by a triad of findings: enlargement of the posterior fossa, cystic dilation of the fourth ventricle, and hypoplasia or agenesis of the cerebellar vermis. The posterior fossa contents are displaced, the tentorium is elevated, and the fourth ventricle communicates with a large posterior fossa cyst. The condition often presents with hydrocephalus, macrocephaly, or other neurological symptoms in infancy, but milder cases may be diagnosed later or remain asymptomatic.

Dandy-Walker malformation is part of the Dandy-Walker complex, which also includes related posterior fossa anomalies such as Dandy-Walker variant and mega cisterna magna. The exact cause is unknown and is likely multifactorial; it may occur as a sporadic event or in association with other brain malformations or genetic syndromes. Genetic associations have been reported, including alterations in ZIC1, ZIC4, and FOXC1 in some cases.

Diagnosis is typically based on imaging. Prenatal ultrasound or fetal MRI can detect the malformation in utero, and postnatal MRI provides detailed anatomy. Management depends on symptoms and may include treatment of hydrocephalus with shunting or other neurosurgical procedures, along with supportive therapies such as physical and developmental interventions. The prognosis is variable and depends on the severity of vermian hypoplasia, the presence of hydrocephalus, and associated anomalies; some individuals have normal development, while others experience persistent motor or cognitive challenges.