Hi thanks for asking question. Usually arachnoid cyst doesn t show any sign and symptoms as in your case. This cyst can be congenital or it is secondary to trauma and infection.But its genetic etiology not well established. This cyst is having purely benign nature.But with the time it can cause symptoms due to compression by increasing size. There is lots of controversy regarding treatment.But usually if cyst small and no symptoms and then treated conservatively with routine clinical and radiological follow up. But it is large space occupying cyst and symptomatic then it has to be removed to prevent developmental delay and seizure like symptoms. The surgical modality include open craniotomy with marsupilization, steariotectic cyst aspiration,ventriculocystostomy. Today laproscopic cyst removal gaining more popularity as it lead to better exposure,less trauma and short hospital stay. I hope i have solved your query well. Thanks for contacting HCM