(410) Great Auricular Nerve Biopsy to Diagnose Squamous Cell Carcinoma Presenting as Progressive Facial Paralysis

Introduction: This case series highlights the use of great auricular nerve (GAN) biopsy to diagnose perineural invasion (PNI) of squamous cell carcinoma in patients presenting with progressive facial paralysis with negative imaging.

Methods: Clinical records of two patients were reviewed, and a literature review was performed. Using external landmarks, the GAN can be found 6.5 cm inferior to the external auditory canal for biopsy.

Results: A 75-year-old male presented for evaluation of progressive left-sided facial paralysis over a 13 month-period. Initial CT/MRI imaging was negative for lesion or nerve enhancement. On the morning of surgery for planned 5-7 nerve transfer, static suspension and extratemporal facial nerve biopsy, he reported worsening facial numbness, and his masseteric bulge was newly-absent. The nerve transfer was cancelled, and biopsies of the facial nerve and GAN in the operating room were positive for squamous cell carcinoma with PNI. The second patient is an 88-year-old male who presented with several weeks of progressive left-sided facial paralysis and a negative CT/MRI. He endorsed numbness of the left ear when questioned. Given the high index of suspicion for neoplastic process, an expedited in-office GAN biopsy was performed. Pathology revealed squamous cell carcinoma with extensive perineural and intraneural invasion. Both patients were referred for prompt treatment with radiation and systemic chemotherapy. Although there have been numerous reports of facial nerve biopsy for the diagnosis of PNI in cases of progressive facial paralysis, this is to our knowledge the first report of a selective GAN biopsy for definitive diagnosis.

Conclusions: Progressive facial paralysis should raise concern for malignant perineural invasion, even in the setting of negative imaging. In such cases, facial nerve biopsy may be performed in the operating room; however, if the patient endorses any associated numbness of the face or ear, work up may be expedited by performing an in-office GAN biopsy, without need for an operating room procedure.