My 14 Year Old Son Was Having Symptoms Of Blurry

My 14 year old son was having symptoms of blurry vision, grey peripheral vision, vertigo, constant dull headache and balance issues. The ER docs called for a CT and this was the result. Can you explain what this means and could this cause his symptoms where it is located? I have read that arachnoid cysts often do not cause symptoms. Concerned mom.
2. Fluid structure contiguous with the quadrigeminal plate cistern on the
left most likely arachnoid cyst. However, given the atypical likely
location for arachnoid cyst and patient's symptoms, MRI of the brain with
gadolinium is recommended to exclude neoplasm.
This was reported via the departmental critical results reporting protocol.