Clinical and radiological presentation, indications to treat, surgical complications, and follow-up were investigated in 40 children with middle fossa arachnoid cysts (MFAC) treated at two centers in Florence, Italy, and Liverpool, UK. Thirty were male and 10 female, mean age 7.8 years, mean follow-up 21 months. Cysts were unilateral, left sided in 28 and right in 12. All underwent endoscopic cystocisternal fenestration as first line surgical treatment. At presentation, intracranial hypertension occurred in 18 (45%), with headache in 15 (37.5%); functional symptoms occurred in 11 (27%) and included head bobbing and speech delay; epilepsy occurred in 8 (20%), and developmental delay in 6 (15%), skull deformity in 9 (22.5%), and focal neurological signs in 8 (20%). Indications for surgery included focal neurological deficits, skull deformities, and/or symptoms or signs of increased intracranial pressure. Epilepsy was an indication only if refractory to medication, if associated with radiological evidence of mass effect and/or increase in size of cyst. Complete resolution of signs and/or symptoms was obtained in 25 (62.5%), and significant improvement in 12 (30%). Headache was relieved in 10 (66%) and improved in 4 (26%), skull deformity improved in all 9 cases (100%), and epilepsy control was improved in 7 (87%). Postoperative complications included subdural hygroma in 5 (12.5%), subdural hemorrhage in 4 (10%) at 3 to 60 months after surgery, and failure of surgery in 4 (10%). Endoscopic fenestration was as effective and safe but less invasive than cyst shunting. [1]

COMMENT. A critical analysis of the surgical treatment of arachnoid cysts is provided in a commentary by Dr C Di Rocco, Rome, Italy [2]. When analyzed objectively, the cause-effect relationship of the “classical” clinical manifestations of temporal arachnoid cyst is questionable. Headaches, reported in about 70% symptomatic cases, are almost always nonspecific and unrelated to cyst volume and intracystic pressure. In patients with epilepsy, the concordance between cyst location and semiology of seizures is rare whereas contralateral EEG abnormalities are common. Intracranial bleeding occurs in 2.2% of patients with MFAC, and this risk was not prevented by surgical operation in the present series. The rate of postoperative subdural hygroma requiring shunt or other surgical treatment is at least 2-fold that reported for spontaneous or posttraumatic hygromas. Other neurosurgeons have expressed similar reservations regarding surgery and especially prophylactic surgery for temporal arachnoid cyst.