Is arachnoid cyst a static disease? A case report and literature review

The increasing use of intracranial imaging has led to more frequent diagnoses of arachnoid cysts (ACs). Although ACs are a frequent finding on neuroimaging in children, the prevalence and natural history of these cysts are not well defined. Most ACs may persist and remain asymptomatic throughout life and not require treatment. However, there have been some case reports of ACs that have become larger or smaller over time and, in rare cases, have even spontaneously resolved. It is the authors' practice to recommend serial neuroimaging in patients with asymptomatic sylvian ACs and not offer surgery to patients without symptoms, even in those with a relatively large cyst.

The present article describes a case involving a 6-year-old boy with a large, asymptomatic AC in the left Sylvian fissure involving the temporo-frontal region, which resolved spontaneously during the 2-year follow-up period after initial diagnosis without any surgical intervention. Currently, at the 7-year follow-up, the patient has remained neurologically intact, attends school, and is symptom-free.

Clinicians should be mindful of the possibility of spontaneous regression when encountering patients with asymptomatic and/or incidentally diagnosed sylvian ACs.