Spontaneous Regression of Pineal Region Arachnoid Cyst: A Case Report and Review of Literature.

Arachnoid cyst is a rare benign cerebrospinal fluid-filled cyst that can develop anywhere in the brain along the arachnoid membrane and usually unaccompanied by the anomalous development of the brain structure. These cysts are usually located in the middle cranial fossa. However, they are also denoted in other regions. Arachnoid cysts are mostly asymptomatic and diagnosed incidentally. Spontaneous regression of arachnoid cysts in different anatomical regions of the brain has been reported in the literature. However, to the best of our knowledge, this is the first case reporting an unusual spontaneous regression of arachnoid cyst in the pineal region in a 3-year-old child presented to our hospital with hydrocephalus without alarming signs and was treated conservatively as the patient was stable, and the cyst showed spontaneous regression. A comprehensive review of the literature regarding spontaneous regression of arachnoid cysts has been collected and discussed in this article.