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)
