Arachnoid Cyst of Internal Auditory Canal: how the Temporal Bone Findings Explain Ear Symptoms and Suggest the Best Treatment to do.
Aim of this short review is to identify relevant findings in clinical and surgical treatment studying arachnoid cyst of internal auditory canal. Retrospective study of relevant papers in literature.
PubMed and Google Scholar searches using the following keywords: arachnoid cyst,
internal auditory canal, temporal bones study, schwannoma of internal auditory canal, cystic
schwannoma, MRI findings, surgery of internal auditory canal.
Only the article where three
keywords, included always arachnoid cyst, were considered. The study analyzed the etiopathogenesis of arachnoid cyst, hearing and vestibular symptoms and temporal bone findings.
The author identified and reviewed a total of 46 articles. The results
showed high incidence of hearing loss that was the more common symptom than vestibular
one. Arachnoid cyst carried out more compression on the vestibular nerves than on the cochlear
The review allowed us to identify which mechanism of damage arachnoid cyst acting on
the nerves. It is necessary to consider the arachnoids cyst in differential diagnosis with tumors
and pathologies involving the internal auditory canal.
Arachnoid Cyst of Internal Auditory Canal is a very rare finding. Sumner and
Thijssen described the first clinical case in the beginning of ’70.1,2 Schucknecht, in 1993, identified this structure in the internal auditory canal of three temporal bones.
Arachnoid cyst can be found in 50% of cases in the Sylvian fissure, in the posterior fossa in 20% and in the Ponto
Cerebellum Angle in 10% of case. In children the higher incidence is in the middle cranial fossa.
The etiology of arachnoid cyst is poorly understood. Congenital/primary and inflammatory
origin/secondary could explain its births and growths.
Otolaryngol Open J. 2016; 2(5): 125-131. doi: 10.17140/OTLOJ-2-128