Investigating the Relationship Between Cerebellopontine Angle Arachnoid Cysts and Sensorineural Hearing Loss in Pediatric Patients

Arachnoid cysts (AC) are benign, cerebrospinal fluid (CSF)-filled sacs. In the cerebellopontine angle (CPA), these cysts may be intimately associated with cranial nerves, the brainstem, and the cerebellum. There are small series associating CPA AC with sensorineural hearing loss, vestibulopathy, and facial paresis. To date, there is a paucity of data regarding factors related to AC that might predict which cysts are associated with sensorineural hearing loss (SNHL). Herein, we investigate the characteristics of AC in the CPA for patients with SNHL.

A single-institution, retrospective study of pediatric patients with AC and audiological evaluations from 2009 to 2024 was conducted. ACs in the CPA were categorized based on contact with the CN VII/VIII complex. The data collected included cyst location, estimated volume, the presence/degree of CN VIII distortion, nerve length, site of contact, and audiologic data. Descriptive statistics analyzed associations between AC and SNHL in the absence of other known pathologies.

A total of 19 patients had 21 ACs involving the CPA. From this group, 11 patients had 11 cysts with contact/distortion of the CN VIII complex (study group), while 8 patients had 10 cysts without contact with the CN VIII (control group). Four (36%) patients in the study group had SNHL ipsilateral to the AC, significantly more than controls ( P <0.03). While the study group had significantly larger cysts ( P <0.03), there was no association with the amount of distortion, length of CN VIII, or contact with the root entry zone (REZ).

Arachnoid cysts in the cerebellopontine angle are associated with ipsilateral SNHL; however, it remains unclear which factors predict SNHL beyond contact/compression of the CN VIII complex. All patients with CPA AC should be referred for audiometric evaluation.