Rare case of a rapidly enlarging symptomatic arachnoid cyst of the posterior fossa in an infant: A case report and review of the literature

Abstract

Background:Intracranial arachnoid cysts are space-occupying lesions that typically remain stable or decrease in size over time. Cysts in infants younger than 1 year of age are remarkably different from those in older children and adults in terms of cyst localization and enlargement. Arachnoid cysts of the posterior fossa (PFACs) are very rare in infants and do not typically grow or present with clinical symptoms, such that surgical treatment is generally considered to be unnecessary. Here, we describe an extremely rare case of an infant with a rapidly enlarging symptomatic PFAC that was successfully treated with surgery.Case Description:A 4-month-old boy presented with increasing head circumference and a rapidly enlarging arachnoid cyst in the left posterior fossa with ventriculomegaly, which was documented using serial imaging over the preceding 2 months. We performed a microscopic resection of the cyst membrane to remove the mass effect as soon as possible and facilitate normal development. To confirm dural closure and prevent cerebrospinal fluid leakage, we also performed short-term (7 days) percutaneous long-tunneled external ventricle drainage after the surgery. Magnetic resonance imaging over a 4-year follow-up period revealed adequate reduction of the ventricle and cyst. The patient no longer exhibited progressive macrocrania and showed normal development.Conclusion:To our knowledge, this is the second successful case of surgical treatment of an enlarging symptomatic PFAC in an infant. Our surgical strategy for the treatment of this rare case can serve as a guide for surgeons in similar future cases.

Arachnoid interamigdal cyst of the posterior fossa in an adult female

“…Hence as informed, cysts in infants can occasionally become enlarged (16.2%). Nevertheless, this feature does not occur in adults 9 . This increase in size is usually secondary to pressure gradient and oscillatory changes with the same diastolic pressure.…”

“…This increase in size is usually secondary to pressure gradient and oscillatory changes with the same diastolic pressure. Other theories mention the fact that the expansion of the cyst may be linked to the direct liquid secretion of the cyst lining by the arachnoid cells that form the wall or by ectopic structures similar to choroids [9][10][11] . Similarly, obstructive hydrocephalus has been described as a common presentation.…”

Endoscopic Fenestration of Posterior Fossa Arachnoid Cysts

“…In the study by Marin-Sanabria et al, the cysts of only 3 of the 23 patients were recognized during routine gestational ultrasounds [9]. The differential diagnosis includes several cystic malformations of the posterior fossa such as Dandy-Walker malformation, Dandy-Walker variant, Blake's pouch cyst and mega cisterna magna [2,3,4,5,16]. The rarity of antenatal diagnosis supports the hypothesis that CSF collection within the cyst increases during the first years of life [9].…”

The Fetal Posterior Fossa on Prenatal Ultrasound Imaging: Normal Longitudinal Development and Posterior Fossa Anomalies

“…Arachnoidalzysten können zu einem obstruktiven Hydrocephalus führen. In den meisten Fällen bleiben sie stabil oder bilden sich zurück, weshalb ein operatives Eingreifen sehr selten notwendig ist [58]. Bei isolierten, postnatal festgestellten, familiär gehäuft aufgetretenen Arachnoidalzysten konnten keine ursächlichen monogenen Veränderungen festgestellt werden [59].…”

“…However, most arachnoid cysts remain stable or decrease in size. Therefore, surgical treatment is generally considered to be unnecessary [58]. The genes associated with arachnoid cysts are unknown [59].…”