A 30-year-old woman presented at NYU Langone with gradually progressive, left-sided facial weakness. After a benign but rare tumor was uncovered, surgeons performed a delicate excision to safely remove the tumor—and restore the patient’s facial function.

A Rare Tumor with an Uncommon Presentation

To uncover the cause of her persistent symptoms, the patient was referred to neurotologist David R. Friedmann, MD, assistant professor in the Department of Otolaryngology—Head and Neck Surgery and part of the team at NYU Langone’s Facial Paralysis and Reanimation Center.

Although Bell’s palsy is a more common cause of facial paralysis, Dr. Friedmann noted that the slow onset of the patient’s facial paralysis was more typical of a tumor. “She had progressive, flaccid paralysis—virtually no movement on that side of her face—which made me suspect a facial neuroma,” he says. “It’s a rare tumor, and even less common to have a patient reach this point, with months of facial weakness, before imaging and diagnosis.”

Results from an MRI revealed evidence of an irregular lesion slightly larger than a centimeter and a CT scan showed a lobulated lesion along the tympanic and mastoid segments of the facial nerve canal. Based on the imaging and clinical history, Dr. Friedmann diagnosed the patient with a left facial nerve schwannoma.

“The tumor grew from the Schwann cells that surround the facial nerve, blocking its normal function—to innervate the muscles of the face,” notes Dr. Friedmann. Though often benign—and managed without surgical intervention if function is relatively intact—this patient’s facial neuroma displayed particularly aggressive features, coupled with functional impairment. He recommended removing the tumor while simultaneously performing a nerve graft to reanimate the nerves of the patient’s face and restore its function.

Tracking the Tumor’s Complex Trail to Enable a Safe Excision

To gain access to the tumor, which spanned multiple segments of the facial nerve, Dr. Friedmann would need to take apart the patient’s ossicles. Since the patient’s tumor presented without the sensorineural hearing loss that can accompany a facial neuroma, excision would need to achieve fully negative margins while also avoiding any hearing loss from damage to the adjacent inner ear.

Through an incision behind the ear, the left mastoid bone was drilled to gain access to the tumor. Its widest point was the mid-mastoid segment and an extension into the mesotympanum adjacent to the stapes in the middle ear. To reach the proximal extent of the tumor, Dr. Friedmann removed the incus, the second of the three middle ear bones, achieving full access to the tumor. He noted that the patient’s normal-appearing facial nerve disappeared into the tumor—providing visual evidence of the mechanism behind her facial paralysis.

Dr. Friedmann realized that complete resection would require taking out a segment of the facial nerve, which he removed along with the tumor. A biopsy was performed, revealing no evidence of residual tumor or malignancy.

Reanimation, Then Rehabilitation

To restore continuity of the facial nerve, Dr. Friedmann harvested a 5-centimeter section of sural nerve from the patient’s right ankle for an interposition graft to bridge the gap in the nerve involved with the tumor, then rebuilt the patient’s hearing bones using an ossicular prosthesis. To protect the patient’s cornea and help the eye close while her facial nerve recovered movement, Payal Patel, MD, clinical assistant professor in the Department of Ophthalmology, implanted a small weight in the patient’s upper eyelid.

“One of the most challenging aspects of the transmastoid approach is accessing the facial nerve without damaging the cochlea and impairing the patient’s intact hearing,” says Dr. Friedmann. “Fortunately, the procedure was successful and we were able to completely preserve both the patient’s inner ear function and conductive hearing while reinnervating her facial musculature—all while avoiding a more invasive neurosurgical approach.”

To help the facial nerve regrow and develop enough muscle tone to control movement, the patient was referred to specialists at NYU Langone’s Rusk Rehabilitation, where facial nerve therapists helped retrain her facial nerves to avoid the “miswiring” that can occur as facial strength returns, and to optimize function with the new nerve.

Six months after surgery, her face demonstrated greater symmetry at rest, without drooping. After nine months, her facial function and appearance were nearly completely restored—and she could smile and close her eyes normally.

“The success of this case is a testament to our multidisciplinary expertise—from our vast experience in complex facial nerve surgeries to our ongoing refinement of rehabilitation approaches,” says Dr. Friedmann. “Everything came together to give this patient with a rare and complex tumor presentation a great outcome.”