A retrospective study on facial nerve schwannomas: a disease with a high risk of misdiagnosis and hearing loss.

The objective is to increase awareness of facial nerve schwannomas (FNSs). Clinical data from 32 cases with FNSs who received surgical treatment from 2005 to 2015 were reviewed retrospectively. The clinical data included age, sex, presentations, duration, facial nerve function, temporal-bone high-resolution computed tomography (CT) and magnetic resonance imaging (MRI) findings, surgical approaches, and postoperative histopathological examination. 16 men and 16 women were included, aged 7-69 years. The average age at diagnosis was approximately 44 years. The mean duration of disease was 65 months, and the mean tumor diameter was 22.4 mm. A tendency of multisegment involvement was observed in 29 FNS cases. Geniculate ganglion and tympanic segments were the most commonly involved segments. Meanwhile, the incidence of misdiagnosis of this disease was 50%. We observed that when FNSs involved the proximal portion of genicular ganglion, the hearing function tended to be worse than when the FNSs only involved the genicular ganglion and/or its distal portion (p < 0.05); in such cases, the hearing loss tended to become more severe with a longer duration of the disorder (p < 0.05). Multiple segment involvement is common in patients with FNS. We need to be more aware of the hearing function when FNSs involve the proximal portion of genicular ganglion. Misdiagnoses of FNS are common, and patients can be misdiagnosed with Bell's palsy, otitis media, or other diseases. Image studies should be conducted for differential diagnosis. Once the decision to perform surgical resection was made, reconstruction of the facial nerve should be considered.