Chapter 11 - Growth and Disappearance of Arachnoid Cysts

Abstract

This chapter gives an overview of reports describing spontaneous disappearance of intracranial arachnoid cysts (ACs), postnatal de novo development, or growth of already established ACs. Based on the number of reports, all these events occur infrequently. Spontaneous AC disappearance appears to be by far the most common event: 27 articles describing a total of 28 patients were retrieved by a literature search; most of the patients were children, only seven were adults. Postnatal de novo ACs development has been described in 26 children, mostly infants, and never in adults. Benign external hydrocephalus appears to predispose for de novo development of ACs in the temporal fossa below the age of 3 years. Growth of an already diagnosed cyst is reported for 26 patients. Most of them were young children; only five were adults. Taken into consideration how infrequently cyst enlargement has been reported in adults or children above the age of 3 years, a strategy of repeated neuroimaging controls to see if an AC increases in size appears irrational in patients older than 3 years-of-age.