Cavum velum interpositum cyst

Case contributed by Dr Alexandra Stanislavsky


Young female with headaches

Patient Data

Age: 25
Gender: Female

Non contrast CT demonstrates a pyramidal (triangular in axial section) CSF density structure located in the midline, separating the thalami and extending as far forward as the foramen of Monro. 


MRI brain

There is a large, well circumscribed mass midline in the pineal region which follows CSF signal on all sequences.  There is no solid component.  

The fornices are splayed and displaced superiorly, and the internal cerebral veins inferiorly.


Annotated images

The velum interpositum (yellow) is located below the columns of the fornices (white arrows) and above the internal cerebral veins (blue) and anterior to the splenium of the corpus callosum (S). When cavum or cystic, it cannot extend beyond the foramen of Monro anteriorly. 

Case Discussion

Midline cyst located between the splayed fornices superiorly and the internal cerebral veins inferiorly.  This is a typical, albeit rare, cyst of the cavum velum interpositum.

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Case information

rID: 21593
Published: 2nd Feb 2013
Last edited: 14th Aug 2019
Inclusion in quiz mode: Included

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