growth hormone and pituitary cysts

My daughter had an MRI 6 months ago because of Horner's syndrome.  Everything came back normal except for a cyst was found on her pituitary gland.  Oh ya, she is now 10.5 months old.  Recently she has dropped off in weight gain and seems to be slowing down developmentally.  We tested her growth hormone and thyroid.  Her growth hormone came back low and her thyroid was normal.  Our doctor is considering rescanning her and we are going to see an endocrinologist.  Could the cyst be developing into something more and affecting the growth hormone?  Does any of this relate to Horner's syndrome?  She is also being tested for Turner syndrome.  Does Turner syndrome come with low growth hormone?  Thanks so much for your response...  

[Godofredo MD]

Hi.

It would be possible, although somewhat uncommon, for the pituitary cyst, if it were large enough and applying significant pressure on the pituitary gland, to disrupt normal pituitary function. In your daughter's case, growth hormone production might have been affected by this.

You should have a neuropediatrician assess your daughter's condition.

Hope this helps.