Following the previous topic of “External hydrocephalus in infants and children”, too many parents have asked about “intracranial arachnoid cysts”. In modern society, especially in the era of only children, parents’ concerns and even anxiety are understandable. Therefore, I would like to summarize and elaborate on this topic with my clinical experience and the relevant literature, hoping that parents can come out of the shadows, out of the misconceptions, and face the disease openly. However, please do not make mechanical judgments by matching numbers or relying too much on this content to avoid delaying the child’s condition. Arachnoid cysts are divided into two categories: congenital and secondary. The former is a histological problem, while the latter is mostly the result of extensive adhesions in the arachnoid membrane due to trauma and inflammation. Congenital arachnoid cysts are pouch-like structures formed by cerebrospinal fluid being enclosed within the arachnoid membrane and not communicating with the subarachnoid space, and are most common. Secondary to arachnoid adhesions, cysts form in the subarachnoid space containing cerebrospinal fluid, mostly as a result of extensive arachnoid adhesions due to trauma and inflammation, and are relatively uncommon. Congenital arachnoid cysts are commonly found at the base of the middle cranial fossa (temporal lobe), the lateral fissure, the longitudinal fissure, the surface or base of the brain, and the cerebellum, as well as in the saddle area, optic nerve, tegmental area, slope, and pontocerebellar horn. Most of the arachnoid cysts are found after incidental factors such as trauma, headache, fever, abdominal pain, nausea and vomiting, etc. Few of them are found after localized cranial augmentation, seizures, hyperactivity, poor memory, limb hemiparesis, and speech dysfunction on film. From then on, parents’ hearts began to hang in the air, even staying awake day and night, looking up information on the Internet and consulting relevant experts. After all, most people in our country have only one child. So, what kind of cysts need to be treated and which ones don’t? Arachnoid cysts that are found incidentally and without obvious symptoms do not require surgical management; about 90% or more of cysts fall into this category. Surgery is only considered for cysts with more definite or obvious symptoms, progressive enlargement of the cyst on periodic review, and significant brain compression. There are three types of surgery: open cystectomy, cyst-abdominal shunt and neuroendoscopic cystostomy with partial excision. The choice of the surgical procedure requires individual judgment and the conditions, equipment and experience of the hospital and doctor consulted. The principle is that the more minimally invasive and the less psychological impact on the child and parents is the preferred method, given the same results. The principle of individualization is advocated, not a one-size-fits-all, mechanical view of the problem, and parents who have this problem are welcome to discuss it after searching for information.