Dandy-Walker variant
Updates to Article Attributes
Dandy-Walker variant (DWv) is a less severe posterior fossa anomaly than the classic Dandy-Walker malformation (DWM), characterised as partial vermian hypoplasia and with partial obstruction to the fourth ventricle. It is considered being on the lesser end of the disease spectrum in the Dandy-Walker continuum.
Terminology
This term was created to include those malformations that do not meet the criteria for Dandy-Walker malformation, however, some authors recommend to avoid it as there is a lack of specificity that may create some confusion. Instead, a more detailed anatomic description is recommended 4.
Please refer to isolated inferior vermian hypoplasia for a broad discussion in this defined entity.
Pathology
There is usually partial vermian hypoplasia with partial obstruction to the fourth ventricle, but without enlargement of the posterior fossa.
Radiographic features
Antenatal ultrasound
- the diagnosis of a Dandy-Walker variant can not be made definitely until the 18th week of gestation as the inferior vermis does not form till then
- may show a connection between the cisterna magna and fourth ventricle
- the fourth ventricle is large but less dilated and better formed than the classic Dandy-Walker malformation 1
- the cerebellar hemispheres are hypoplastic but there is less severe hypoplasia of the inferior vermis
Differential diagnosis
On antenatal ultrasound consider:
- communication between the fourth ventricle and the cisterna magna can be a normal finding up to ~18 weeks of gestation
- incorrect angulation of the scan may make the posterior fossa larger than usual
See also
-<p><strong>Dandy-Walker variant (DWv)</strong> is a less severe posterior fossa anomaly than the classic <a href="/articles/classic-dandy-walker-malformation">Dandy-Walker malformation (DWM)</a> and is considered being on the lesser end of the disease spectrum in the <a href="/articles/dandy-walker-continuum-3">Dandy-Walker continuum</a>.</p><h4>Terminology</h4><p>This term was created to include those malformations that do not meet the criteria for Dandy-Walker malformation, however, some authors recommend to avoid it as there is a lack of specificity that may create some confusion. Instead, a more detailed anatomic description is recommended <sup>4</sup>.</p><p>Please refer to <a href="/articles/isolated-inferior-vermian-hypoplasia">isolated inferior vermian hypoplasia</a> for a broad discussion in this defined entity.</p><h4>Pathology</h4><p>There is usually partial <a href="/articles/vermian-hypoplasia">vermian hypoplasia</a> with partial obstruction to the <a href="/articles/fourth-ventricle">fourth ventricle</a>, but without enlargement of the posterior fossa.</p><h4>Radiographic features</h4><h5>Antenatal ultrasound</h5><ul>- +<p><strong>Dandy-Walker variant (DWv)</strong> is a less severe posterior fossa anomaly than the classic <a href="/articles/classic-dandy-walker-malformation">Dandy-Walker malformation (DWM</a>), characterised as partial <a title="Isolated inferior vermian hypoplasia" href="/articles/isolated-inferior-vermian-hypoplasia">vermian hypoplasia</a> with partial obstruction to the <a href="/articles/fourth-ventricle">fourth ventricle</a>. It is considered on the lesser end of the disease spectrum in the <a href="/articles/dandy-walker-continuum-3">Dandy-Walker continuum</a>.</p><h4>Terminology</h4><p>This term was created to include those malformations that do not meet the criteria for Dandy-Walker malformation, however, some authors recommend to avoid it as there is a lack of specificity that may create some confusion. Instead, a more detailed anatomic description is recommended <sup>4</sup>.</p><p>Please refer to <a href="/articles/isolated-inferior-vermian-hypoplasia">isolated inferior vermian hypoplasia</a> for a broad discussion in this defined entity.</p><h4>Pathology</h4><p>There is usually partial <a title="Isolated inferior vermian hypoplasia" href="/articles/isolated-inferior-vermian-hypoplasia">vermian hypoplasia</a> with partial obstruction to the <a href="/articles/fourth-ventricle">fourth ventricle</a>, but without enlargement of the posterior fossa.</p><h4>Radiographic features</h4><h5>Antenatal ultrasound</h5><ul>
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