Patient History

The most important initial step in the evaluation of a patient with facial paralysis is taking an accurate history of the onset of the facial weakness. Extratemporal causes are usually associated with gradual-onset facial weakness, peripheral branch involvement, or fluctuating facial weakness.4 Acute facial paralysis rarely is caused by an extratemporal neoplasm. Localized pain, referred otalgia, or trismus should alert the clinician as to the possibility of an extratemporal malignancy causing facial paralysis. Pain in this region is due to neoplastic involvement of the sensory branches of the trigeminal nerve.5 Patients should also be questioned about any prior skin cancer treatment in the scalp or facial region as deep tumor invasion or lymphatic spread can cause ipsilateral facial paralysis.

Physical Examination

The exact extent of the presenting facial weakness must be accurately made and documented. Facial photography at rest and during animation should be made part of the patient′s medical record. Dynamic facial function can also be video-recorded and stored in the patient′s electronic medical record.

Neck and parotid gland palpation must be carefully performed in an effort to identify cervical lymph node metastases or a primary parotid neoplasm. The ipsilateral auricle, temporal scalp, and facial regions should be inspected for skin cancers that may directly invade the facial nerve or spread to parotid lymph nodes. The oral cavity must also be inspected and palpated as deep-lobe or parapharyngeal space tumors may not be externally visible or palpable. Any degree of trismus, due to tumor invasion of the ptygoid muscles or the temporomandibular joint, can also be assessed during the oral cavity examination.6

Microscopic otoscopic examination is performed as some parotid neoplasms either originate in the temporal bone or may involve the ear canal by direct cartilaginous or bony invasion.7 Finally, a complete cranial nerve assessment is performed as occult, deep parotid tumors may invade the jugular foramen causing lower cranial nerve dysfunction, and perineural spread along the trigeminal nerve may lead to cavernous sinus extension and deficits of cranial nerves III, IV, or VI.

Diagnostic Studies

The radiological assessment of a palpable parotid mass in a patient with facial paralysis can be accomplished with either contrast-enhanced computed tomography (CT) or magnetic resonance imaging (MRI).8 Perineural extension is better evaluated with MRI coronal views with special attention to the trigeminal nerve and the cavernous sinus ( Fig. 15.1 ).9 Temporal bone invasion, especially at the stylomastoid foramen, is better evaluation with high-resolution CT imaging ( Fig. 15.2 ). Nonpalpable tumor invasion of the facial nerve by primary parotid malignancies of adjacent skin cancers may only be seen on MRI selective views.10

The assessment of metastatic disease can be accomplished with CT or MRI views of the brain, chest, and abdomen, or whole-body positron emission tomography scanning. Peripheral bone, spine, or joint pain may suggest bone metastases, which are best evaluated with a whole-body radionucleotide bone scan.

Tissue Biopsy

Fine-needle aspiration cytology may provide a preoperative tissue diagnosis, although inaccurate results may lead to inappropriate surgical treatment. Tru-cut or core biopsy is contraindicated in the evaluation of parotid neoplasms due to the risk of tumor seeding or injury to the uninvolved portion of the facial nerve. Parotidectomy with biopsy and permanent (not frozen-section) histology is the most accurate means of making the correct diagnosis.