Abstract
Background Facial paralysis due to cancer can be misdiagnosed as Bell's palsy. This study aims
to clearly identify and quantify diagnostic differentiators and further evaluate the
prognostic implications of misdiagnosis.
Methods Adult patients older than 18 years with facial palsy of unknown or cancerous etiology
presenting between 2009 and 2023 were reviewed. Patient characteristics, examination
findings, and clinical course were compared between facial paralysis patients with
cancer misdiagnosed as Bell's palsy (Cancer-Bell's-Palsy group) and patients correctly
diagnosed with Bell's palsy (Bell's-Palsy group). Additionally, morbidity and mortality
were compared between facial paralysis patients with cancer initially misdiagnosed
with Bell's palsy and facial paralysis patients initially correctly diagnosed with
cancer (Cancer-Palsy group).
Results Two-hundred and forty-three patients participated including 43 Cancer-Palsy, 18 Cancer-Bell's-Palsy,
and 182 Bell's-Palsy patients. Cancer-Bell's-Palsy patients were significantly less
likely than Bell's-Palsy patients to develop synkinesis (odds ratio [OR] = 0.0042;
95% confidence interval [CI]: [0.0005–0.0339]; p < 0.0001), significantly more likely to experience gradual onset facial paralysis
(OR = 1,004.69; 95% CI: [54.40–18,555.77]; p < 0.0001), and significantly more likely to have additional nonfacial cranial nerve
neuropathies (OR = 49.98; 95% CI: [14.61–170.98]; p < 0.0001). Cancer-Bell's-Palsy patients were more likely than Cancer-Palsy patients
to have a greater than 6-month period from initial cancer-attributable symptom onset
to cancer diagnosis (OR = 47.62; 95% CI: [9.26–250.00]; p < 0.001), stage IV cancer (OR: 12.36; 95% CI: 1.49–102.71; p = 0.006), and decreased duration of life after cancer diagnosis (median [interquartile
range], 40.0 [87.0] vs. 12 [56.3] months, respectively; p = 0.025).
Conclusion Facial paralysis related to cancer must be differentiated from Bell's palsy, as misdiagnosis
leads to delayed intervention and poorer prognosis. Gradual onset facial palsy, multiple
cranial nerve neuropathies, lack of synkinesis, and lack of improvement were nearly
definitive differentiators for underlying cancer.
Keywords
facial palsy - cancer - Bell's palsy
