Atypical Tumors of the Facial Nerve

Case Series and Review of the Literature

Lindsey Ross, M.D; Doniel Drazin, M.D; Paula Eboli, M.D; Gregory P. Lekovic, M.D., Ph.D.

Disclosures

Neurosurg Focus. 2013;34(3):e2 

In This Article

Illustrative Cases

Case 1

This 52-year-old woman presented with a 2-month history of right facial weakness. She developed Bell palsy on the right side more than 10 years previously, which had resolved within a few days with steroids and antiviral medication. This time, however, she did not respond to steroids. For this reason, MRI and CT scanning of the temporal bone were performed. These studies showed a right 10 × 12–mm skull base lesion situated within the right mastoid with some degree of contrast enhancement consistent with a neoplasm (Fig. 1). Differential considerations included glomus tumor and schwannoma. On examination, the patient was intact except for facial weakness (House-Brackmann Grade III). The patient underwent a right transtemporal craniotomy including mastoidectomy and decompression of the sigmoid sinus with microsurgical resection of the extradural skull base paraganglioma and decompression of the vertical segment of the facial nerve from the facial recess to the stylomastoid foramen. Surgical pathology was compatible with paraganglioma. The patient had worsening facial paresis postoperatively (House-Brackmann Grade VI) that at last follow-up (13 months) improved back to the preoperative level (House-Brackmann Grade III); there has been no progression of residual tumor.

Figure 1.

Preoperative axial precontrast (A), postcontrast T1-weighted (B), and T2-weighted (C) MR images revealing a right 10 × 12–mm skull base lesion situated within the right mastoid.

Case 2

This 77-year-old man presented with left facial weakness that progressed over a period of 9 months. Magnetic resonance imaging with and without contrast showed a left temporal tumor, which involved the vertical segment of the facial nerve (Fig. 2). The CT scan showed an expansive lytic process involving the left facial nerve region. Differential diagnosis included neoplastic processes arising from the facial nerve or from the jugular fossa involving the facial nerve. On examination, he was intact except for severe facial weakness (House-Brackmann Grade VI). The patient underwent the following procedures: postauricular intratemporal craniotomy with microsurgical resection of the facial nerve schwannoma, interposition graft of the facial nerve with a collagen tubule and 15-cm harvest of the sural nerve, parotidectomy, and tympanoplasty with ossicular reconstruction. The surgical specimen was compatible with a schwannoma (WHO Grade I). At last follow-up (12 months), the patient had no significant improvement in facial nerve function and was referred for a facial sling procedure.

Figure 2.

Preoperative axial precontrast (A) and postcontrast T1-weighted (B and C) MR images revealing a left temporal tumor, which involves the vertical segment of the facial

Case 3

This 49-year-old man presented with right ear fullness lasting 1 year and 1 episode of dizziness 2 years prior (from which he had a full recovery). Magnetic resonance imaging and CT temporal bone studies showed a right enhancing temporal bone mass and enlargement of the facial nerve along the geniculate ganglion, most consistent with hemangioma followed by facial nerve schwannoma and meningioma (Fig. 3). On physical examination, the patient was intact. The patient underwent a combined transmastoid and middle fossa craniotomy with resection of extradural skull base tumor and tegmen reconstruction. Surgical pathology was compatible with meningioma (WHO Grade I). Although he continued to have some right ear pressure, the patient's otological examination revealed normal findings.

Figure 3.

Preoperative temporal bone CT scan (A) and axial precontrast (B), postcontrast T1-weighted (C), and T2-weighted (D) MR images demonstrating a right enhancing temporal bone mass and enlargement of the facial nerve along the geniculate ganglion.

Case 4

This 37-year-old woman presented with a 5-year history of vertigo. Three years later she developed Bell palsy. Since then, she has complained of left facial weakness and synkinesis and received Botox injections in January 2010. Despite this treatment, she continued to have facial weakness. Findings from initial imaging, including MRI performed 5 years earlier, were thought to be negative. Subsequent imaging demonstrated slight irregular enhancement of the labyrinth and geniculate segment of the facial nerve. Her CT scanning examination showed an ossified lytic spiculated lesion in the area of the geniculate segment of the facial nerve (Fig. 4). On physical examination, the patient was intact except for mild left facial asymmetry and House-Brackmann Grade I–II left facial weakness. Differential diagnosis included an inflammatory process versus a benign neoplasm such as facial nerve schwannoma or hemangioma. The patient underwent a left middle fossa craniotomy for resection of the tumor and facial nerve decompression. Surgical pathology was compatible with hemangioma. Postoperatively, she did well and her face was symmetric (House-Brackmann Grade I).

Figure 4.

Preoperative axial postcontrast T1-weighted MR image (A) and axial CT images (B and C) showing a spiculated lesion in the area of the geniculate segment of the facial nerve.

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