TEACHING POINTS
■ Bell palsy occurs when the nerve that controls facial muscles on one side of the face becomes swollen or inflamed.
■ Diagnosis is primarily made with a thorough examination of the affected areas to rule out items in the differential diagnosis. A good clinical understanding of the anatomy of cranial nerve VII helps aid the diagnosis.
■ A surgical approach with intraoperative margin control such as Mohs micrographic surgery may be the best treatment approach, as it has very low recurrence rates.
■ When in doubt, additional testing is warranted and referral to a specialist is in the patient's and PA's best interests.
■ Outcomes are generally good unless the patient has basal cell carcinoma that reaches the nerve, at which point both morbidity and mortality rates increase.
CASE
In April 2008, a 78-year-old male presented at the University of Utah's National Comprehensive Cancer Network (NCCN) institution with recurrent basal cell carcinoma in the left preauricular area (Figure 1). His dermatologist had referred him for Mohs micrographic surgery to remove the tumor in question. An original biopsy of the left cheek lesion, obtained from the referring physician's office, demonstrated a morpheaform basal cell carcinoma. A second biopsy of the eyebrow obtained at the NCCN was also positive for morpheaform basal cell carcinoma. The history was significant only for persistent Bell palsy. Upon additional questioning, the patient stated that he had been unable to close his left eyelid or control muscles on the left side of his face for more than 4 years. During this time, he had been seen multiple times by various medical providers. Based on his symptoms, each provider suspected Bell palsy. The tumor on the preauricular cheek was thought to be a scar from a previous excision. Over time, it became evident that this case warranted further investigation.
Treatment At the NCCN, multiple courses of Mohs surgery were performed on the left cheek and eyebrow. At the time, the surgeons and clinicians did not anticipate that the cancer had spread to cause the Bell palsy. Negative margins were confirmed on the eyebrow after one stage. However, negative margins on the left cheek could not be confirmed after three stages. The resection, done under local anesthesia, was stopped when it reached the masseter muscle, the superficial parotid gland, and lymph nodes because a transition to general anesthesia would have been required.
The tumor was found to have grown into the parotid gland with extensive perineural invasion involving the facial portions of cranial nerve VII. Infiltrative basal cell carcinoma was also discovered on the patient's ipsilateral brow. This tumor was aggressive, required multiple stages of surgery, and had invaded the branches of the supraorbital nerve from cranial nerve V. Because the surgical defect was so large, a specialist in oncologic head and neck surgery was called in to perform the reconstruction and attempt to salvage nerve function if possible. At this point, it was thought that the patient's symptoms resembled those of Bell palsy (seventh cranial nerve palsy) and presumably resulted from the basal cell carcinoma.
The head and neck surgeon agreed that further Mohs surgery was not appropriate given the depth of the tumor and proximity of the auditory canal. MRI failed to show the presence of residual bulky tumor or nodal disease. An additional margin was resected under general anesthesia, and negative margins were histopathologically confirmed. The resulting defects were repaired with adjacent tissue transfer flaps, providing the patient with a satisfactory cosmetic outcome. Unfortunately, function of the facial nerve was unsalvageable. The patient was referred for a course of postoperative radiation to eliminate any tumor cells that might have been missed during surgery.
Outcome In June 2008, a gold weight was inserted into the patient's left eyelid, which was successful in assisting with functional closure of the left eyelid in supine position. In January 2009, the patient was sent to physical therapy in an attempt to regain some function in what remained of the left facial muscles. Secondary to resection of the nerve, little to no improvement of facial muscle function was reported by the patient. This case identifies another diagnosis to consider when Bell palsy is suspected and highlights the need for clinicians to take a thorough history and physical examination even when the diagnosis seems evident.