Treatment tactics for ruptured arachnoid cysts of the lateral fissures

This article presents a case report of a 3‑year-old, 9‑month-old child with an arachnoid cyst in the left temporal region complicated by rupture. Approximately two weeks prior to presentation, the patient suffered a traumatic brain injury, after which his parents began noticing lethargy in the evenings. Gradually, he developed headaches, eye pain, which bothered the child even at night, and vomiting several times a week. A cyst was detected during the initial CT scan, but there was no urgent indication for surgery. Nine days later, the child’s condition worsened: a follow-up MRI revealed an increase in the meningeal mass to 9.6 mm and a 3 mm displacement of the midline structures. The ophthalmologist diagnosed grade I–II optic disc edema, which was an indication for surgical treatment. The child underwent endoscopic fenestration of the cyst and placement of a lumbar drain for 8 days. The surgery was successful, with no complications. A follow-up MRI three weeks later showed a reduction in the meningeal masses and brain displacement. This case demonstrates that endoscopic surgery with temporary CSF drainage produces good results for ruptured cysts in children.