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March 2013

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When facial nerve paralysis is not Bell's Palsy...
About Dr. Malin

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Dear Colleague,     

 

March's ENT E-Update features Barry T. Malin, M.D., MPP, who describes the findings of an MUSC study of patients with occult skin cancers of the head and neck in which cranial neuropathy was the sole presenting symptom of advanced cutaneous neoplasia.

 

Dr. Malin joined the MUSC Department of Otolaryngology - Head & Neck Surgery, Head & Neck Oncology Division in July 2012 as an Assistant Professor after completing his fellowship with the department.

 

You can find more information about Dr. Malin below and on our website. Please feel free to contact us with your feedback or questions about our E-Udate articles, your patients, or any other ENT issue at entupdate@musc.edu.

 

Paul R. Lambert, MD

Professor and Chair

Dr. Mailin in clinic
Barry T. Malin, MD, MPP
Assistant Professor, Head & Neck Oncology
When facial nerve paralysis is not Bell's Palsy...

Cranial neuropathies due to "occult" advanced skin cancer of the head and neck

Cranial neuropathies, particularly facial nerve paralysis or trigeminal paresthesia, are frequent presenting complaints in an Otolaryngology practice. Although the vast majority of such complaints are inflammatory in origin, the clinician must remain vigilant in identifying the subset of cases in which facial paralysis or other cranial neuropathies stem from a neoplastic cause.

An uncommonly reported, but likely underdiagnosed, cause of cranial neuropathy involves unrecognized perineural spread of cutaneous neoplasia of the head and neck. At MUSC, we are currently completing a study of a cohort of patients who presented with occult skin cancers of the head and neck in which cranial neuropathy was the sole presenting symptom of advanced cutaneous neoplasia. Patients in the study were initially referred for evaluation of a cranial neuropathy and subsequently found to have advanced perineural invasion of a cranial nerve due to skin cancer in the absence of any identifiable skin lesions on initial examination.

Although there are sporadic case reports of cranial neuropathies as the initial presenting symptom at a substantial interval following previous excision of squamous cell skin cancers, this phenomenon has not been well-described.1 New onset facial paralysis, hypesthesia or neuralgia may be the initial manifestation of perineural spread occurring months or years after skin cancer excisions, but is often unrecognized by the clinician.2 Solares and colleagues describe clinical perineural invasion as the development of cranial deficits and radiologic evidence of cranial nerve invasion by cutaneous squamous cell carcinoma and report that symptoms commonly emerge years after the excision of cutaneous lesions.3

Review of patient records from the Hollings Cancer Center at MUSC over a ten year period (2001 - 2011) revealed 17 patients who presented with a cranial neuropathy but no active skin lesions and were subsequently found to have advanced perineural spread of skin cancer but no observable skin cancer at the time of initial evaluation. Initial findings from the study were presented this year at the 8th International Congress on Head and Neck Cancer, and the full study including a meta-analysis encompassing all comparable cases reported in the English literature is forthcoming.

All patients in the MUSC series were Caucasian with a strong male predominance (88%) and an average age of 70. A wide range of presenting neurological symptoms was noted, including the following (in order of descending frequency): CN VII facial paralysis, facial numbness, facial neuralgia or parasthesias, CN V paralysis, diplopia and dysgeusia. However, all patients in the series had either CN V or CN VII involvement on presentation.

Histopathologic analysis of the involved cranial nerve either at surgical resection or biopsy demonstrated invasion of the cranial nerve by squamous cell carcinoma in all cases, although two cases additionally demonstrated basaloid features or overlapping basal cell carcinoma. A key finding in the study was the prolonged time interval between the onset of symptoms and subsequent diagnosis of unrecognized cranial nerve invasion by skin cancer, with an average time interval of 17 months between initial recognition of cranial neuropathy and diagnosis of occult invasion by cutaneous squamous neoplasia. Many patients in the series had previously undergone multiple resections of cutaneous lesions, making identification of the index lesion difficult. In cases where the index lesion was determined, the most common location was the scalp, followed by the periauricular region and the cheek.

Treatment protocol at MUSC's Hollings Cancer Center for patients who presented with prolonged cranial neuropathies of unexplained origin entails obtaining contrast-enhanced MRI imaging. Suggestive findings include cranial nerve enhancement or thickening or widening of involved neural foramina.
Figure 1
Enhancement of left CN V2 [white arrow] in a patient with occult perineural invasion by squamous cell carcinoma. White arrowhead demonstrates normal CN V2 on right side. 
Figure 2
MRI of a patient with perineural invasion of the left mandibular nerve due to occult spread of cutaneous squamous cell carcinoma demonstrates CN V3 enhancement within the foramen ovale [white arrow]. Normal CN V3 designated on right [arrowhead].
Figure 3
MRI demonstrates enhancement of left mandibular nerve [white arrow] into the skull base due to unrecognized perineural invasion of CN V3 by cutaneous squamous cell carcinoma in a patient with no visible cutaneous lesions at presentation. Normal CN V3 [arrowhead] on right.

Biopsy of the CN V or CN VII at the level of the brainstem is utilized to document cerebral extension. In our series, 4/17 patients were biopsy-proven to have brainstem involvement and were thus treated non-operatively with chemoradiation. Overall, 9/17 patients were treated with radical surgical resection.

  

The recognition that a patient presenting with CN V or CN VII neuropathies may in fact be suffering from perineural invasion by skin cancer when no obvious skin lesions are present on examination presents a challenging diagnostic scenario. However, recognition of this phenomenon is critically important, particularly in South Carolina, which has among the highest rates in the nation of cutaneous neoplasia. Timely diagnosis is essential, as prognosis worsens with central progression. It is therefore important to recognize factors that suggest occult perineural invasion as the cause of a cranial neuropathy. Prior treatment of skin cancer of the head and neck is the primary risk factor, particularly in the context of multiple neuropathies or if accompanied by facial paresthesia.4 Other key discriminating factors are listed in the table below.

  

  

Key Factors Suggestive of Perineural Invasion

by Skin Cancer as the Cause of Cranial Neuropathy

 

 

Involvement of multiple cranial nerves (especially concurrent involvement of CN V and CN VII).

 

Progressive or indolent onset of CN VII paralysis.

 

Paralysis of individual CN VII branches.

  

Persistence of CN VII paralysis beyond 6 months without remission.

 

Patient perception of formication in a CN V distribution.   

 

 

  

Clinical Pearl

  

 

All patients with new onset with CN V or CN VII neuropathies should be questioned regarding prior skin cancers of the scalp or face and sun exposure history, even if no concerning skin lesions are present upon initial examination.

 

Prolonged treatment based on presumption of an inflammatory cause for cranial neuropathy such as Bell's Palsy or Trigeminal Neuralagia can have grave prognostic implications in the setting of unrecognized clinical perineural spread of skin cancer.

 

   

Barry T. Malin , M.D., MPP

Assistant Professor

MD: University of California at San Francisco 

Residency: State University of New York 

Fellowship: MUSC 

Special Interests: Head and neck tumors and microvascular reconstructive surgery

SELECTED REFERENCES

  

1 Menhanna H, John S, Morton R, et al. Facial palsy as the presenting complaint of perineural spread from cutaneous squamous cell carcinoma of the head and neck. ANZ J Surg. 2007;77:191-193.

 

2 Catalano J, Sen C, Biller H. Cranial neuropathy secondary to perineural spread of cutaneous malignancies. Am J Otol. 1995;16(6):772-777.

 

3 Solares C, Lee K, Parmar P, et al. Epidemiology of clinical perineural invasion in cutaneous squamous cell carcinoma of the head and neck. Otolaryng Head Neck. 2012;146(5):746-751.

 

4 Boahene D, Olsen K, Driscoll C, et al. Facial nerve paralysis secondary to occult malignant neoplasms. Otolaryng Head Neck. 2004;130:459-465.


About Dr. Malin... Barry Malin

 


Barry T. Malin , M.D., MPP

Assistant Professor

MD: University of California at San Francisco 

Residency: State University of New York

MPP: Harvard University 

Fellowship: MUSC 

Special Interests: Head and neck tumors and microvascular reconstructive surgery

 

Medical University of South Carolina Department of Otolaryngology - Head & Neck Surgery

135 Rutledge Avenue, MSC 550, Charleston, SC 29425|Phone: 843.792.8299|Website: ENT.musc.edu|� 2013