Connatal cyst

Last revised by Daniel J Bell on 7 Jun 2022

Connatal cysts, also known as coarctation of the lateral ventricles or frontal horn cysts, are cystic areas adjacent to the superolateral margins of the body and frontal horns of the lateral ventricles and are believed to represent a normal variant.

The incidence is <1% (range 0.4-6%) 4.

It was previously believed to be a sequela of different insults in the developing brain 2, however, it seems to be just a normal variant 1,3 secondary to focal coarctation (i.e. apposition/fusion) of the lateral ventricle walls 4. The outward most part of the ventricle attains a rounded appearance when the ventricle walls are close enough and touching each other. This gives a cystic appearance sonographically. 

  • thin-walled cysts in the superior and lateral aspect of frontal horn of lateral ventricle and anterior to the foramina of Monro
  • most often multiple cysts noted
  • a string of pearls appearance may be seen

They have been shown to regress on follow-up imaging when demonstrates in infants <2 months of age 4

Considerations include:

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Cases and figures

  • Case 1
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  • Case 2: on MRI in an adult
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  • Case 3
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