inter hemispheric cyst detected at 19+4

[Cuppachaplz]

I had a detailed anomaly scan yesterday following a high risk Downs blood test (1 in 48) at 17 weeks. DH and I had declined amnio as I have a history of RMC (15 at various stages) and to us the risk was not justifiable, and a Downs baby would not bother us.
The detailed scan showed no cardiac abnormalities, no cranial diameter to femoral length disproportion, no neck thickening, no visible facial abnormalities, and no liver or kidney abnormalities. It is too early to assess the bowel. The baby lies on the 30th centime, which has been the case throughout, and is very active. They did however find a small cyst, probably sub-arachnoid, lying between the hemispheres of the brain, measuring 8mm.
They have told me that this could be incidental and may spontaneously regress, but they will continue to monitor and advise accordingly. I have my 20 week scan next Monday, where they will presumably check again, an I have to return to foetal medicine in 2 weeks for a repeat scan and assessment. I have also been told that I can choose to have an amnio at this stage too.
Does anyone have any experience of such an abnormality; did it go away?
I am desperately trying to avoid a pub med search or Dr. Google in an effort to keep calm, but not finding it easy to ignore a brain lesion.
Thanks

[JiltedJohnsJulie]

No advice sorry just wanted to let you know I'm here

[Cuppachaplz]

Thanks julie
I'm guessing from the lack of responses saying 'I had that, and it was gone at the next scan' that it's fairly uncommon.
I can't help worrying and thinking that a cystic lesion within the limited space of the skull can only be somewhat worse that any DS
Most people seem to keep saying that no DS markers is good, but downs not ruled out by the lack of markers, whereas I wasn't too bother about DS, but a brain lesions sounds dreadful...