Dandy-Walker Malformation
Dandy-Walker malformation is a rare congenital brain anomaly characterized by complete or partial underdevelopment of the cerebellar vermis, cystic enlargement of the fourth ventricle and expansion of the posterior fossa. Hydrocephalus accompanies a significant proportion of cases, and the course varies over a wide range.
마지막 업데이트: 2026-06-07
Definition
Dandy-Walker malformation (DWM) is a rare congenital posterior fossa malformation defined by complete or partial absence of the cerebellar vermis, cystic enlargement of the fourth ventricle and expansion of the posterior fossa. It results from disturbed posterior fossa development during the embryonic period (around weeks 8-12 of gestation), and underdevelopment of the fourth ventricle outlet foramina can affect CSF circulation.
Spectrum
DWM is regarded as a spectrum. Classic Dandy-Walker malformation combines marked underdevelopment of the vermis, cystic enlargement of the fourth ventricle and expansion of the posterior fossa. In milder variants the vermis is partly preserved and the cyst is smaller. Mega cisterna magna is a benign variant with a normal vermis and only an enlarged cisterna magna, usually without symptoms. This distinction matters for prognosis and follow-up.
Associated Conditions
Hydrocephalus accompanies a significant proportion of cases. DWM can often occur with other brain and body anomalies, including disorders of the corpus callosum, cortical developmental anomalies, cardiac anomalies and renal anomalies. It may be part of certain genetic syndromes (Walker-Warburg, Joubert, Meckel-Gruber) and chromosomal anomalies. The presence of associated anomalies markedly influences the course.
Symptoms
In infancy and early childhood, symptoms are usually related to hydrocephalus: rapidly increasing head circumference (macrocephaly), a tense fontanelle, irritability, feeding difficulty and vomiting. Underdevelopment of the vermis may cause imbalance and a wide-based gait (ataxia), involuntary eye movements (nystagmus) and developmental delay. Milder cases may come to attention in later childhood or adulthood with headache, balance problems or learning difficulty.
Diagnosis
Diagnosis may be suspected before birth on ultrasonography (a posterior fossa cyst and absent vermis from around 18-20 weeks) and fetal MRI; prenatal diagnosis warrants genetic counseling and screening for other organ anomalies. After birth, brain MRI is the reference method and demonstrates underdevelopment of the vermis, the fourth ventricle cyst, posterior fossa enlargement and hydrocephalus. The differential diagnosis includes mega cisterna magna, posterior fossa arachnoid cyst and Blake's pouch cyst. Neurodevelopmental assessment helps in monitoring the course.
Treatment
Treatment mainly involves managing hydrocephalus and controlling symptoms. When hydrocephalus develops, the first choice is usually a ventriculoperitoneal shunt, and programmable valves may be preferred. In selected obstructive cases, particularly in older infants, endoscopic third ventriculostomy can be an alternative, though success rates may be limited in DWM. Large, symptomatic posterior fossa cysts rarely require cyst drainage or decompression. Neurodevelopmental support through early intervention programs, physical therapy, occupational therapy, speech therapy and special education is an important part of care.
Course
The course is highly variable and depends largely on associated anomalies. A significant proportion of isolated DWM cases follow a normal or mildly delayed course, while more serious developmental involvement may occur when additional brain anomalies or a genetic syndrome are present. Balance problems related to absence of the vermis often persist to some degree, although functional adaptation is possible. Outcomes vary markedly between patients and none can be guaranteed; multidisciplinary follow-up is advised.
참고 문헌
- Greenberg MS. Greenberg's Handbook of Neurosurgery. 10th ed. Thieme; 2023:270-272.
- Winn HR, ed. Youmans Neurological Surgery. 6th ed. Saunders; 2011:1906-1910.
- Spennato P, Mirone G, Nastro A, et al. Hydrocephalus in Dandy-Walker malformation. Childs Nerv Syst. 2011;27(10):1665-1681.
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