Facial palsy from metastatic nasopharyngeal carcinoma at various sites: Three reports. (Original Article).
Nasopharyngeal carcinoma that causes clinically evident facial palsy is uncommon. This article describes and discusses a series of cases that illustrates how nasopharyngeal carcinoma caused facial palsy as a result of facial nerve involvement at three sites: the cerebellopontine angle, the middle ear, and the parotid. The maxim, "All that palsies is not Bell's," is particularly relevant with respect to patients who have previously been treated for advanced nasopharyngeal carcinoma. In these patients, recurrent or persistent nasophatyngeal carcinoma involving the cerebellopontine angle, temporal bone, or parotid should be excluded.
Tumor involvement of the facial nerve is estimated to cause 5% of all cases of peripheral facial paralysis. (1) After emerging from the brainstem, the facial nerve enters the cerebellopontine angle, the temporal bone (including the internal auditory canal, middle ear, and mastoid), and the parotid before branching out to supply the facial muscles. Tumor involvement of the nerve anywhere along this course can cause facial palsy. Facial nerve palsy caused by nasopharyngeal carcinoma is uncommon; its incidence is less than 1%. (2) Even though clinically evident facial palsy from metastatic tumors is rare, subclinical involvement of the facial nerve is not uncommon. (1)
Nasopharyngeal carcinoma is an interesting disease. It has a distinct racial predilection, being common in Chinese from southern China. A higher incidence is seen among the family members of affected patients, suggesting that genetics might play a significant role in its etiology. In Hong Kong, patients with nasopharyngeal carcinoma have been found to eat greater amounts of preserved food, such as salted fish. Moreover, virologic, immunologic, and molecular studies have shown a close association between nasopharyngeal carcinoma and Epstein-Barr virus. A model that incorporates virologic, genetic, and environmental factors has been suggested by Liebowitz. (3)
Signs of nasopharyngeal carcinoma can be conveniently grouped into several categories: nasal complaints, otologic manifestations, cervical nodal metastases, cranial nerve deficits, and distant metastases, among others. In patients with cranial nerve deficits, the facial nerve is seldom involved. (2)
This article describes a series of three cases in which facial palsy was caused by involvement of the facial nerve by nasopharyngeal carcinoma at three different points along the nerve's course, and it includes an explanation of the clinical significance of each case.
Patient 1. A 40-year-old man had a 1-year history of a left tinnitus and a swollen left cervical lymph node. Within the postnasal space was a mass, which was histologically identified as a poorly differentiated nasopharyngeal carcinoma (T3N2). The tumor extended to the medial part of the infratemporal fossa and parapharynx.
Six months after treatment with a course of radical radiotherapy, the patient complained of left facial palsy. Examination revealed a complete left lower motor neuron facial palsy; the other cranial nerves were intact. Computed tomography (CT) showed that the tumor involved the cerebellopontine angle (figure 1). Despite another course of radiotherapy, the patient died 6 months later.
Patient 2. A man 51 years of age was evaluated for left middle ear effusion. Examination of the postnasal space detected a mass, which was confirmed by histology to be a moderately differentiated squamous cell carcinoma. A diagnosis of nasopharyngeal carcinoma (T3NO) was made, and the patient was treated with a radical course of radiotherapy, which led to a resolution of symptoms. However, 2 months after the completion of radiotherapy, the patient again complained of hearing loss on the left.
He sought treatment elsewhere, and an otolaryngologist diagnosed left middle ear effusion. Myringotomy and ventilation tube insertion were performed.
Approximately 3 weeks later, the patient returned to us for treatment after he developed a left facial palsy and left facial numbness. He was then noted to have a complete left lower motor neuron facial palsy and a loss of sensation to touch and pain over the mandibular nerve distribution of the skin. His left ear was infected and purulent. Magnetic resonance imaging and CT detected a tumor mass in the deeper aspect of the left postnasal space, with involvement of the left cavernous sinus, sphenoid sinus, and petrous apex. The left foramen ovale and foramen spinosum, as well as the horizontal part of the left internal carotid canal, were eroded, and the tumor extended through the anterior wall of the middle ear (figure 2).
During surgical exploration, the tumor mass was found in the attic and mesotympanum and could be traced to the carotid canal. Biopsy of the mass identified a moderately differentiated squamous cell carcinoma that was identical to the original nasopharyngeal carcinoma. The patient was treated with palliative chemotherapy and died 4 months later.
Patient 3. A 50-year-old man was treated for nasopharyngeal carcinoma overseas. Two years later, he exhibited a complete left lower motor neuron facial nerve palsy. Examination revealed a hard mass in the left parotid over the region of the facial trunk in addition to multiple swollen cervical nodes (figure 3). The postnasal space was clinically free of tumor, and the appearance of the ears was unremarkable. Chest x-ray showed multiple metastases. Analysis of a fine-needle aspiration sample of the parotid mass identified an undifferentiated carcinoma consistent with metastatic nasopharyngeal carcinoma. The patient refused further treatment and died 3 months later.
Involvement at the cerebellopontine angle. Gouliamos et al described two cases of nasopharyngeal carcinoma that metastasized to the cerebellopontine angle. (4) Metastasis to this site has been attributed to the hematogenous route, to dissemination via cerebrospinal fluid, and to leptomeningeal spread. (5)
In this series, patient 1 already had advanced disease when he was first evaluated. Under the standard procedure for administering radiotherapy to treat nasopharyngeal carcinoma, the brainstem is routinely shielded from irradiation in order to avoid myelitis. As a result, the cerebellopontine angle is in the low gradient and there is a possibility of undertreatment of even microscopic disease. Geographic undertreatment might have been the reason that this patient returned later with clinical manifestations of cerebellopontine angle involvement by nasopharyngeal carcinoma. (6)
Besides the facial nerve, nasopharyngeal carcinoma in the cerebellopontine angle can involve the VIIIth cranial nerve and thereby cause a sensorineural hearing loss and giddiness. Making an accurate clinical diagnosis of cerebellopontine angle involvement is not necessarily a straightforward process because patients who undergo radiotherapy for nasopharyngeal carcinoma often develop hearing loss and giddiness as a delayed effect of the treatment itself on the inner ear.
Once nasopharyngeal carcinoma has involved the cerebellopontine angle, treatment becomes more challenging. Localized disease can be treated with radiosurgery. Larger tumors can require the use of chemotherapy to debulk the tumor before standard radiotherapy is administered. Treatment can be further complicated if the tumor spreads from the cerebellopontine angle to the internal auditory meatus. (6)
Involvement in the ear. Kwong et al noted that tumor metastasis to the middle or outer ear is uncommon; only 17 cases were reported between 1966 and 1995. (7) These tumors included those that had spread from the breast, prostate, testis, colon, paranasal sinus, bladder, lung, and nasopharynx. Berlinger et al believed that intracranial tumors could involve the temporal bone as a result of either direct extension, hematogenous or lymphatic spread, meningeal carcinomatosis, or leptomeningeal extension. (8) It has been proposed that the routes of spread of nasopharyngeal carcinoma to the middle ear are via the eustachian tube and via direct invasion from the parapharyngeal space. (7) The case of patient 2 illustrates an alternate route, in which nasopharyngeal carcinoma spread from the cavernous sinus, through the carotid canal, and into the middle ear.
The incidence of middle ear invasion of nasopharyngeal carcinoma is probably higher than what has been reported, considering the anatomic communication and close proximity. (7) Middle ear invasion by nasopharyngeal carcinoma can be misdiagnosed as postradiotherapy middle ear effusion. This was illustrated in the case of patient 2, where tumor invasion of the middle ear was mistaken for middle ear effusion, for which myringotomy and ventilation tube insertion were performed.
Involvement in the parotid. Metastatic cancers to the parotid account for less than 10% of all parotid cancers. (9) When they do occur, up to 80% of parotid metastases arise from cutaneous lesions in the head and neck. (10) Infraclavicular sources (e.g., the lung, breast, and kidneys) are rare. Of the primary sources in the upper aerodigestive tract, the nasopharynx is the most common. (11)
Of the possible routes of parotid spread (i.e., direct invasion, lymphatic spread, and hematogenous dissemination), lymphatic spread is the most common. (10) The parotid is made up of a network of lymphatic vessels and interconnecting intraglandular and periglandular lymph nodes. Nasopharyngeal carcinoma can affect the retropharyngeal lymph nodes, which can drain into the parotid nodes. From the parotid nodes, the tumor has access to the lymphatic plexus, parotid parenchyma, facial nerve, and even the parapharyngeal space. (11)
The relatively high possibility that nasopharyngeal carcinoma will metastasize to the parotid prompted Batsakis and Bautina to caution against too readily accepting a diagnosis of "primary undifferentiated carcinoma of nasopharyngeal type." (11) Wanamaker et al correctly pointed out that it is important to differentiate the two, from both a diagnostic as well as a therapeutic standpoint. (10)
The maxim, "All that palsies is not Bell's," (12) is particularly relevant with respect to patients who have previously been treated for advanced nasopharyngeal carcinoma. In these patients, exclusion of recurrent or persistent nasopharyngeal carcinoma in the cerebellopontine angle, temporal bone, or parotid is warranted.
From the Department of Otolaryngology, Singapore General Hospital.
Reprint requests: Dr. Wong-Kein Low, Department of Otolaryngology, Singapore General Hospital, Singapore 169608, Republic of Singapore. Phone: +65-321-4488; fax: +65-226-2079; e-mail: email@example.com
(1.) Jung TT, Jun BH, Shea D, Paparella MM. Primary and secondary tumors of the facial nerve. A temporal bone study. Arch Otolaryngol Head Neck Surg 1986;112:1269-73.
(2.) Skinner DW, Van Hasselt CA, Tsao SY. Nasopharyngeal carcinoma: Modes of presentation. Ann Otol Rhinol Laryngol 1991;100:544-51.
(3.) Liebowitz D. Nasopharyngeal carcinoma: The Epstein-Barr virus association. Semin Oncol 1994;21:376-81.
(4.) Gouliamos AD, Athanassopoulou A, Moulopoulou L, et al. MRI of nasopharyngeal carcinoma metastatic to the cerebellopontine angle. Neuroradiology 1996;38:375-7.
(5.) Yuh WT, Mayr-Yuh NA, Koci TM, et al. Metastatic lesions involving the cerebellopontine angle. AJNR Am J Neuroradiol 1993;14:99-106.
(6.) Low WK, Fong KW, Chong VF. Cerebellopontine angle involvement by nasopharyngeal carcinoma. Am J Otol 2000;21:871-6.
(7.) Kwong DL, Yuen AP, Nicholls J. Middle ear recurrence in two patients with nasopharyngeal carcinoma. Otolaryngol Head Neck Surg 1998;118:280-2.
(8.) Berlinger NT, Koutroupas S, Adams G, Maisel R. Patterns of involvement of the temporal bone in metastatic and systemic malignancy. Laryngoscope 1980;90:619-27.
(9.) Bergersen PJ, Kennedy PJ, Kneale KL. Metastatic rumours of the parotid region. Aust N Z J Surg 1987;57:23-6.
(10.) Wanamaker JR, Kraus DH, Biscotti CV, Eliachar I. Undifferentiated nasopharyngeal carcinoma presenting as a parotid mass. Head Neck 1994;16:589-93.
(11.) Batsakis JG, Bautina E. Metastases to major salivary glands. Ann Otol Rhinol Laryngol 1990;99:501-3.
(12.) Clemis JD. All that palsies is not Bell's: Bell's palsy due to adenoid cystic carcinoma of the parotid. Am J Otol 1991;12:397.
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|Comment:||Facial palsy from metastatic nasopharyngeal carcinoma at various sites: Three reports. (Original Article).|
|Publication:||Ear, Nose and Throat Journal|
|Article Type:||Brief Article|
|Date:||Feb 1, 2002|
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