Facial Nerve Schwannoma Complicated by Acute Hemorrhage Posttreatment with Stereotactic Radiosurgery

Background: Facial nerve schwannomas (FNSs) are rare benign tumors arising from Schwann cells of the facial nerve. In the last decade, stereotactic radiosurgery (SRS) has shown promise in stabilizing or shrinking FNSs.

Case Description: A 71-year-old female patient presented with left facial palsy [House-Brackmann (H-B) 3/6]. MRI showed a 1.85 cm left cerebellopontine angle (CPA) mass that follows the facial nerve trajectory to the geniculate ganglion, most consistent with FNS (Fig. 1A). After 5 months of watchful waiting, a serial MRI demonstrated interval increase in tumor size to 2.15 cm (Fig. 1B).

Fig. 1

Treatment with CyberKnife® was recommended (21 Gy/3 fractions) (Fig. 2A). Three days after receiving the first fraction, the patient presented to the emergency department with sudden onset of severe headache, dizziness, imbalance, and worsening of facial palsy (H-B ⅚). She was somnolent; an urgent CT showed a hemorrhagic left CPA mass measuring 3.5 cm, with displacement and compression of the brainstem and fourth ventricle (Fig. 2B).

Fig. 2

Surgical intervention was recommended. A transotic approach achieved a successful near-total resection of the FNS (Fig. 3A), where a small remnant was left over a loop of the AICA. The involved facial nerve segment was resected, and a cadaveric donor was used to connect the midportion of the tympanic segment and the stump originating from the brainstem (Fig. 3B).

Fig. 3

Histological examination demonstrated schwannoma with infiltration of tumor cells into the facial nerve fascicles (Fig. 4).

Fig. 4

As expected, the patient progressed to a complete H-B 6/6 facial palsy; Platinum-Gold eye weight insertion was performed to protect the left eye from dryness and injury. The patient was sent to rehab and stayed for 10 days until she regained her baseline functional independence, except for facial palsy, after which she was discharged home.

Discussion: To our knowledge, this report documents the first case of intratumoral hemorrhage in a patient with FNS, which occurred acutely (within 3 days) after receiving SRS with CyberKnife.

Intratumoral hemorrhage in vestibular schwannomas (VSs) is estimated at around 0.4%.[1] However, a rate as high as 18% has been reported following SRS.[2] By extrapolating hemorrhage rates from VSs, we wonder whether the hemorrhagic occurrence in our patient was due to the pathophysiologic effects of SRS on the tumor or it was a simple coincidence.

In hemorrhagic VSs, facial nerve dysfunction is much more common (33%) upon presentation compared with nonhemorrhagic VSs (6%), and mortality is significantly increased as well (10% vs 0.2%).[2] Our patient's clinical deterioration due to the acute posterior fossa hemorrhage necessitated surgical intervention, the promptness of which, we believe, was the main factor for the patient's quick return to baseline status.

Conclusion: While SRS remains the treatment of choice for FNSs, symptomatic hemorrhagic transformation may be life-threatening, yet can be successfully managed with prompt surgical resection and cable nerve anastomosis with good functional outcome, except for the expected facial palsy.

No conflict of interest has been declared by the author(s).

• References

• Carlson ML, Tombers NM, Driscoll CLW, et al. Clinically significant intratumoral hemorrhage in patients with vestibular schwannoma. Laryngoscope 2017; 127 (06) 1420-1426
• Niknafs YS, Wang AC, Than KD, Etame AB, Thompson BG, Sullivan SE. Hemorrhagic vestibular schwannoma: review of the literature. World Neurosurg 2014; 82 (05) 751-756