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 Dandy walker Cyst

Clinical details :  21Y/F  G4A2L1    Routine scan

Findings     : Dilated lateral ventricles.
                  Cystic transformation of 4th ventricle.
                  Vermis of Cerebellum is absent.

Diagnosis   : Dandy walker cyst.

Discussion Exact origin of DW cyst is unknown Etiology. Theories include failure of development of roof of the 4th ventricle, Atresia of 4th ventricular outlet foramina & delayed opening of the foramen of magendie.

                  4th ventricle shows cystic dilatation with variable degree of Cerebellar & Vermis Hypoplasia. In severe cases the cyst occupies most of posterior Fossa. Generalized
obstructive Hydrocephalus in 80% of DW cyst. Other CNS abnormalities are present
in 70% of cases. These include Corpus Callosum agenesis.

DWC should differentiated from Mega Cisterna magna in which 4th ventricle, ventricular system  is normal.

                  Another deferential diagnosis is posterior Fossa Anachamoid cyst in which 4th Ventricle & Cerebellum are displaced anteriorly.

Reference  : RCNA VOL.28 1990  Diagnostic Ultrasound by Carol M. Rumack, St. R. Wilson, J. William Charboneau

Submitted by : Dr. Adinarayana Rao. M. D &  Dr. C. Savitri. M. D. (OBG & GYN)

2000 Radiologyworld.com