Object
Interhemispheric arachnoid cysts are very rare, and they are often associated with complex brain malformations such as corpus callosum agenesis and hydrocephalus. Debate remains concerning the proper management of these lesions. Placement of shunts and microsurgical marsupialization of the cyst are the traditional options. Using endoscopic methods to create areas of communication between the cyst, the ventricular system, and/or the subarachnoid space is an attractive alternative to the use of shunts and microsurgery.
Methods
Between 2000 and 2005, seven consecutive pediatric patients with interhemispheric arachnoid cysts underwent neuroendoscopic treatment involving cystoventriculostomy in two patients, cystocisternostomy in two, and cystoventriculocisternostomy in three. There were three cases of associated hydrocephalus, six cases of corpus callosum agenesis, and one case of corpus callosum hypogenesis.
The follow-up period ranged from 12 to 49 months (mean 31.6 months). Endoscopic procedures were completely successful in all but two patients. In one of the remaining two patients, a repeated endoscopic cystocisternostomy was performed with success because of closure of the previous stoma. In the other, a subcutaneous collection of cerebrospinal fluid (CSF) was managed by insertion of a lumboperitoneal shunt. A subdural collection of CSF developed in three patients; it was treated with insertion of a subduroperitoneal shunt in one patient and managed conservatively in the other two patients, resolving spontaneously without further treatment. Neurodevelopmental evaluation performed in six patients showed normal intelligence (total intelligence quotient [IQ] > 80) in three patients, mild developmental delay (total IQ 50–80) in two, and severe developmental delay (total IQ < 50) in one.
Conclusions
Endoscopic treatment of interhemispheric cysts can be considered a useful alternative to traditional treatments, even if some complications are to be expected, such as subdural or subcutaneous CSF collections and CSF leaks due to thinness of cerebral mantle and to the often-associated multifactorial hydrocephalus.
Management of giant symptomatic frontal arachnoid cyst with corpus callosum agenesis in an adult resembling interhemispheric arachnoid cyst