Isolated facial palsy from perineural spread of cutaneous squamous cell carcinoma

Biopsy of the facial nerve in slow-onset facial palsy

INTRODUCTION

Primary squamous cell carcinoma of the parotid gland typically presents as a palpable, often painless mass. Peripheral facial palsy as the only sign of malignant neoplasia is rare. In these cases, the diagnosis is regularly confirmed by radiological imaging followed by surgical exploration and biopsy. However, if there is no detection of malignant lesions and no evidence of a tumor, the reluctance to take a biopsy of an unremarkable nerve can lead to misdiagnoses.

CASE REPORT

A 40-year-old female patient without medical history presented to our clinic with a complete right-sided peripheral facial palsy that had slowly progressed for 2.5 years. All other otorhinolaryngological examination findings were within normal limits. Magnetic resonance imaging examination of the head and neck and 18-fluorodeoxyglucose positron emission tomography showed unremarkable results. We proceeded with surgical exploration, which revealed no evidence of a tumor and an externally completely unremarkable facial nerve. A biopsy from the main trunk area of the nerve revealed an infiltration by a squamous cell carcinoma. Total parotidectomy with resection and reconstruction of the facial nerve and neck dissection was performed. Considering the absence of a primary tumor and other tumor formations the diagnosis of a completely regressive primary squamous cell carcinoma of the parotid gland was confirmed.

CONCLUSION

In conclusion, in the case of slow-onset peripheral facial palsy that persists without signs of recovery, a gadolinium-enhanced MRI should be performed. If imaging is unremarkable and there is no primary tumor detection along the course of the facial nerve, a surgical exploration with biopsy of the facial nerve is necessary.

Slowly progressive facial paralysis: Intraneural squamous cell carcinoma of unknown primary

BACKGROUND

In this report, we present a unique case of intraneural squamous cell carcinoma of unknown primary found within the facial nerve and the proposed algorithms for diagnosis and management of progressive idiopathic facial paralysis.

CASE PRESENTATION

A 66-year-old female with a previous history of basal cell carcinoma presented with right-sided progressive facial paralysis. Repeated magnetic resonance imaging as well as targeted workup failed to reveal a diagnosis. 20 months following symptom onset, after the patient's facial function slowly progressed to a complete paralysis, repeat magnetic resonance imaging revealed enhancement at the stylomastoid foramen. The patient underwent superficial parotidectomy, transmastoid facial nerve decompression and resection of descending and proximal extratemporal facial nerve segments, as well as great auricular nerve interposition grafting. Intraoperatively, frozen sections from the surface of the facial nerve, and the proximal and distal segments of the facial nerve following resection, were negative for malignancy. The final pathology revealed infiltrating poorly differentiated squamous cell carcinoma of the facial nerve with negative margins.

CONCLUSION

In cases of slowly progressive facial paralysis the clinician needs to consider malignancy until proven otherwise. Without an identifiable primary malignancy, early algorithmic assessment of presenting characteristics may facilitate expedited clinical decision making and surgical management of malignancy involving the facial nerve. In cases of slowly progressive facial paralysis, when the time comes for surgical exploration and biopsy, head and neck surgeons must be aware that malignancy can exist entirely within the facial nerve, without pathologic changes on the surface of the nerve or in the surrounding tissue.