Facial Neuromas Misdiagnosed as Recurrent or Idiopathic Palsy: A Systematic and Institutional Review

To evaluate the incidence of recurrent facial palsy and the frequency of misdiagnosis as Bell's palsy in patients with intratemporal facial nerve schwannomas (FNSs)Methods:A systematic review of PubMed and Cochrane databases and a single-institutional analysis were conducted, covering studies from the past 10 years on adult cases of intratemporal FNS with documented facial nerve function at presentation. Inclusion criteria focused on patients presenting with facial paralysis to assess recurrence rates and misdiagnoses as Bell's palsy. Key outcomes included incidence, severity, and the number of prior facial paralysis episodes at the time of FNS diagnosis.

From 284 studies identified, 77 full texts were reviewed, and 53 met inclusion criteria, totaling 531 patients. Among the 531 patients, 55.6% (295) initially presented with facial paralysis. We found that 4.5% (24) of all patients in the systematic review and 22.2% (2) of cases in our institutional review with an intratemporal FNS were initially misdiagnosed with Bell's palsy. Of those who presented with facial paralysis, misdiagnosis as Bell's palsy was noted in 8.14% (24) of the systematic review and 100% (2) of our institutional review. The average House-Brackmann (HB) scores worsened from initial presentation to pre-operative assessment (mean scores: 2.07 ± 1.49 vs 2.94 ± 1.73).

Our single-institutional and systematic review emphasizes that facial paralysis is a common presenting symptom of FNS. Although idiopathic (Bell's) palsy is the most frequent cause of facial paralysis, it remains a diagnosis of exclusion and a neoplastic cause should be ruled out in certain cases. A high index of suspicion is warranted for persistent (>3 months) or recurrent facial palsy, particularly when accompanied by otologic symptoms. Early identification of FNS enables timely interventions, such as facial nerve decompression, which may preserve native nerve function.