Close
New

Medscape is available in 5 Language Editions – Choose your Edition here.

 

Intratemporal Tumors of the Facial Nerve Workup

  • Author: Jacek Szudek, MD, PhD; Chief Editor: Arlen D Meyers, MD, MBA  more...
 
Updated: Mar 11, 2016
 

Laboratory Studies

See the list below:

  • Because the diagnosis of Bell palsy is one of exclusion, the astute otolaryngologist must rule out other causes of acute progressive facial nerve paralysis. Bell palsy does typically not present with hearing loss; the absence of hearing thus should alert the clinician to further investigate the possibility of a facial nerve tumor.
  • A detailed head and neck examination should be performed, with focus on certain physical examination findings.
  • Evaluation of facial nerve status
    • Have the patient repeat facial movements; assess for subtle asymmetry.
    • Observe for involuntary facial twitching.
    • Evaluate the eyelids: Ask the patient to close the eye; attempt to lift up the eyelid with your finger. Note any asymmetry between sides.
    • Evaluate for scleral show and corneal dryness. Referral to an ophthalmologist may be necessary.
    • Consider photographs.
    • Use an objective classification scheme, such as the House-Brackmann scale, to document the extent of facial weakness or paralysis.
  • Evaluation of the external, middle, and inner ear
    • Perform pneumatic otoscopy; observe for a possible mass.
    • Tuning fork examinations should be performed. The presence of conductive or sensorineural hearing loss should be documented.
    • Consider obtaining an audiogram, especially if the history or physical findings include hearing loss.
  • Evaluation of the neck
    • Pay particular attention to the parotid region. A mass may be present.
    • A thorough neck examination for adenopathy should also be performed.
Next

Imaging Studies

See the list below:

  • CT scanning
    • High-resolution, thin-cut CT imaging of the temporal bone is believed to be superior to MRI for visualization of bony structures.
    • High-resolution CT imaging of the temporal bone with axial and coronal views can aid in localization of tumor margins and involvement or erosion of adjacent structures.
    • A tumor along the course of the intratemporal facial nerve does not have to be very large to be symptomatic. Additionally, nonspecific enhancement of the nerve is commonly observed. Therefore, by defining the bony anatomy, CT scanning can add confirmatory or exclusionary evidence of the presence of these tumors.
    • Bony spicules within hemangiomas are also sometimes noted, which may be helpful in differentiating these lesions from schwannomas.
  • Gadolinium-enhanced MRI of the posterior fossa and temporal bones
    • MRI is the criterion standard for assessing soft tissue, such as the facial nerve. It provides specific information regarding perineural invasion and soft tissue involvement.
    • Facial nerve neuromas can arise from any facial nerve segment. Therefore, all facial nerve segments should be imaged and studied in detail.
    • This study is helpful in determining whether a larger size tumor is present. Obtaining MRI is not necessary in every case of Bell palsy because MRI results do not change the initial management. However, if a tumor is suspected, perform MRI. Note that tumors of the intratemporal facial nerve might escape MRI visualization because of their size. The most common histopathologic types (schwannoma and hemangioma) appear as enhancing lesions on T1-weighted images.
    • Radiographically distinguishing between an intracanalicular seventh nerve tumor and vestibular schwannomas is often impossible. Frequently, this rare diagnosis is made intraoperatively.
Previous
Next

Other Tests

See the list below:

  • Audiologic testing and immittance measures
    • A pure tone audiogram should be obtained.
    • Stapedial reflexes should be performed, although they are not always reliable indicators of distal facial nerve function.
  • Electroneuronography
    • Surgical intervention for facial nerve tumors is initiated once a patient's facial nerve function has deteriorated to the point at which the expected result would be nearly equivalent to the patient's current function (ie, House-Brackmann grade III or IV).
    • Because of this, serial electroneuronography (ENog) evaluations are helpful as a quantitative measure to augment the patient's self-assessment and the physician's observations.
  • Facial nerve action potential
    • Facial nerve action potential (FNAP) is a valid method for assessing facial nerve function waveform.
    • Facial nerve schwannomas are extremely slow growing and frequently present without facial dysfunction.
  • Photography
    • Photography of resting and dynamic facial nerve function also augments the physician's serial assessment of the deteriorating facial nerve.
    • Postoperative comparison is also made possible.
Previous
Next

Histologic Findings

The 2 most common tumors found along the course of the intratemporal facial nerve are schwannomas and hemangiomas. Schwannomas are well-circumscribed, encapsulated masses that arise from Schwann cells. They tend to splay rather than to invade the nerve fibers. Surgical removal of these tumors while sparing the nerve is possible, with better results in terms of postoperative function. They are firm gray masses that may have areas of cystic and xanthomatous change. They are characterized by bland palisading cells with slender nuclei.

The 2 classic conformations are the Antoni A and Antoni B patterns. The Antoni A pattern demonstrates elongated cells with cytoplasmic processes arranged in fascicles in areas of moderate to high cellularity with little stromal matrix; the nuclear-free zones of processes that lie between the regions of nuclear palisading are termed Verocay bodies. In the Antoni B pattern, the tumor is less cellular with a loose meshwork of cells along with microcysts and myxoid changes. Because the tumor displaces the nerve of origin as it grows, silver stains or immunostains for neurofilament proteins reveal axons that are largely excluded from the tumor. These tumors are immunoreactive to S-100. Malignant change is extremely rare, although local recurrence can occur with incomplete resection.

Hemangiomas are highly vascular lesions that consist of endothelium-lined channels. These tumors are lobulated but unencapsulated aggregates of closely packed, thin-walled capillaries, usually blood filled, and separated by scant connective tissue stroma. The lumina may be partially or completely thrombosed and organized. Rupture of vessels causes scarring and leads to the occasional hemosiderin pigment. Because of the proclivity of hemangiomas to be found near the geniculate ganglion, neuronal cell bodies and bone fragments often accompany the histologic specimen.

Of note, a histological specimen from the mastoid segment that demonstrates fibroadipose tissue without nerve tissue indicates a facial nerve pseudocyst, which is treated with surgical excision.

Previous
 
 
Contributor Information and Disclosures
Author

Jacek Szudek, MD, PhD Resident Physician, Department of Otolaryngology-Head and Neck Surgery, University of Alberta, Edmonton

Jacek Szudek, MD, PhD is a member of the following medical societies: College of Physicians and Surgeons of Alberta, Royal College of Physicians and Surgeons of Canada, Canadian Medical Protective Association

Disclosure: Nothing to disclose.

Coauthor(s)

Nader Sadeghi, MD, FRCSC Professor, Otolaryngology-Head and Neck Surgery, Director of Head and Neck Surgery, George Washington University School of Medicine and Health Sciences

Nader Sadeghi, MD, FRCSC is a member of the following medical societies: American Head and Neck Society, American Thyroid Association, American Academy of Otolaryngology-Head and Neck Surgery, Royal College of Physicians and Surgeons of Canada

Disclosure: Nothing to disclose.

K Paul Boyev, MD Director of Hearing and Balance Center, Assistant Professor, Department of Otolaryngology-Head and Neck Surgery, University of South Florida

K Paul Boyev, MD is a member of the following medical societies: American Academy of Otolaryngology-Head and Neck Surgery, American Medical Association

Disclosure: Nothing to disclose.

Arjun S Joshi, MD Assistant Professor of Surgery, Division of Otolaryngology–Head and Neck Surgery, George Washington University School of Medicine and Health Sciences

Arjun S Joshi, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Otolaryngology-Head and Neck Surgery, American College of Surgeons, American Head and Neck Society, American Medical Association, American Thyroid Association

Disclosure: Nothing to disclose.

Alan A Z Alexander, MD, MS George Washington University School of Medicine

Alan A Z Alexander, MD, MS is a member of the following medical societies: American Medical Association, American Medical Student Association/Foundation, American Psychiatric Association

Disclosure: Nothing to disclose.

Specialty Editor Board

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Received salary from Medscape for employment. for: Medscape.

Gerard J Gianoli, MD Clinical Associate Professor, Departments of Otolaryngology-Head and Neck Surgery and Pediatrics, Tulane University School of Medicine; President, The Ear and Balance Institute; Board of Directors, Ponchartrain Surgery Center

Gerard J Gianoli, MD is a member of the following medical societies: American Otological Society, Society of University Otolaryngologists-Head and Neck Surgeons, Triological Society, American Neurotology Society, American Academy of Otolaryngology-Head and Neck Surgery, American College of Surgeons

Disclosure: Serve(d) as a director, officer, partner, employee, advisor, consultant or trustee for: Vesticon<br/>Received none from Vesticon, Inc. for board membership.

Chief Editor

Arlen D Meyers, MD, MBA Professor of Otolaryngology, Dentistry, and Engineering, University of Colorado School of Medicine

Arlen D Meyers, MD, MBA is a member of the following medical societies: American Academy of Facial Plastic and Reconstructive Surgery, American Academy of Otolaryngology-Head and Neck Surgery, American Head and Neck Society

Disclosure: Serve(d) as a director, officer, partner, employee, advisor, consultant or trustee for: Cerescan;RxRevu;SymbiaAllergySolutions<br/>Received income in an amount equal to or greater than $250 from: Symbia<br/>Received from Allergy Solutions, Inc for board membership; Received honoraria from RxRevu for chief medical editor; Received salary from Medvoy for founder and president; Received consulting fee from Corvectra for senior medical advisor; Received ownership interest from Cerescan for consulting; Received consulting fee from Essiahealth for advisor; Received consulting fee from Carespan for advisor; Received consulting fee from Covidien for consulting.

Additional Contributors

Michael E Hoffer, MD Director, Spatial Orientation Center, Department of Otolaryngology, Naval Medical Center of San Diego

Michael E Hoffer, MD is a member of the following medical societies: American Academy of Otolaryngology-Head and Neck Surgery

Disclosure: Received royalty from American biloogical group for other.

References
  1. Gross BC, Carlson ML, Moore EJ, Driscoll CL, Olsen KD. The intraparotid facial nerve schwannoma: a diagnostic and management conundrum. Am J Otolaryngol. 2011 Dec 19. [Medline].

  2. Warren HG, Prevatt AA, Daly KA, Antonelli PJ. Cellular telephone use and risk of intratemporal facial nerve tumor. Laryngoscope. 2003 Apr. 113(4):663-7. [Medline].

  3. Doshi J, Hughes R, Freeman SR, et al. Clinical and Radiological Guidance in Managing Facial Nerve Schwannomas. Otol Neurotol. 2014 Oct 1. [Medline].

  4. Edizer DT, Hajizade Y, Karaman E, Cansiz H. Intraparotid facial nerve neurofibroma in neurofibromatosis type 1. J Craniofac Surg. 2011 May. 22(3):1118-9. [Medline].

  5. Kim J, Moon IS, Lee JD, Shim DB, Lee WS. Useful surgical techniques for facial nerve preservation in tumorous intra-temporal lesions. Auris Nasus Larynx. 2010 Feb. 37(1):33-41. [Medline].

  6. Lahlou G, Nguyen Y, Russo FY, Ferrary E, Sterkers O, Bernardeschi D. Intratemporal facial nerve schwannoma: clinical presentation and management. Eur Arch Otorhinolaryngol. 2015 Dec 16. [Medline].

  7. Lu R, Li S, Zhang L, Li Y, Sun Q. Stripping surgery in intratemporal facial nerve schwannomas with poor facial nerve function. Am J Otolaryngol. 2015 May-Jun. 36 (3):338-41. [Medline].

  8. Chung JW, Ahn JH, Kim JH, Nam SY, Kim CJ, Lee KS. Facial nerve schwannomas: different manifestations and outcomes. Surg Neurol. 2004 Sep. 62(3):245-52; discussion 452. [Medline].

  9. Donzelli R, Maiuri F, Peca C, Cavallo LM, Motta G, de Divitiis E. Microsurgical repair of the facial nerve. Zentralbl Neurochir. 2005 May. 66(2):63-9. [Medline].

  10. Frosch MP, Anthony DC, De Girolami U. The Central Nervous System. Kumar V, ed. Robbins and Cotran Pathologic Basis of Disease. 7th ed. Philadelphia, Pa: WB Saunders; 2004. 1401-20.

  11. Isaacson B, Telian SA, McKeever PE, Arts HA. Hemangiomas of the geniculate ganglion. Otol Neurotol. 2005 Jul. 26(4):796-802. [Medline].

  12. Kirazli T, Oner K, Bilgen C, Ovül I, Midilli R. Facial nerve neuroma: clinical, diagnostic, and surgical features. Skull Base. 2004 May. 14(2):115-20. [Medline].

  13. Marzo SJ, Zender CA, Leonetti JP. Facial nerve schwannoma. Curr Opin Otolaryngol Head Neck Surg. 2009 Jun 24. [Medline].

  14. McMonagle B, Al-Sanosi A, Croxson G, Fagan P. Facial schwannoma: results of a large case series and review. J Laryngol Otol. 2008 Nov. 122(11):1139-50. [Medline].

  15. Minovi A, Vosschulte R, Hofmann E, Draf W, Bockmuhl U. Facial nerve neuroma: surgical concept and functional results. Skull Base. 2004 Nov. 14(4):195-200; discussion 200-1. [Medline].

  16. Perez R, Chen JM, Nedzelski JM. Intratemporal facial nerve schwannoma: a management dilemma. Otol Neurotol. 2005 Jan. 26(1):121-6. [Medline].

  17. Perez R, Chen JM, Nedzelski JM. Intratemporal facial nerve schwannoma: a management dilemma. Otol Neurotol. 2005 Jan. 26(1):121-6. [Medline].

  18. Schoen FJ. Blood Vessels. Kumar V, ed. Robbins and Cotran Pathologic Basis of Disease. 7th ed. Philadelphia, Pa: WB Saunders; 2004. 545-51.

  19. Shirazi MA, Leonetti JP, Marzo SJ, Anderson DE. Surgical management of facial neuromas: lessons learned. Otol Neurotol. 2007 Oct. 28(7):958-63. [Medline].

 
Previous
Next
 
A small acoustic neuroma within the internal auditory canal is easily observed on postgadolinium MRI.
 
 
 
All material on this website is protected by copyright, Copyright © 1994-2016 by WebMD LLC. This website also contains material copyrighted by 3rd parties.