Rapidly progressive epithelioid malignant peripheral nerve sheath tumor of the vestibular nerve.

OBJECTIVE

Spontaneous malignant peripheral nerve sheath tumors (MPNSTs) arising from the vestibular nerve are extremely rare. In this report, we detail the case of one such tumor including the first report of its response to radiosurgery.

PATIENTS

A 73-year-old woman presented with subacute sensorineural hearing loss, retroauricular pain, and facial nerve palsy.

INTERVENTIONS

Magnetic resonance imaging (MRI) was obtained demonstrating findings suggestive of a vestibular schwannoma. The patient elected for gamma knife radiosurgery and 13 gray were administered to the lesion. Repeat MRIs showed that the mass quickly regressed after radiosurgery but recurred by 5 months. Subsequent microsurgical resection revealed an aggressive epithelioid MPNST of the vestibular nerve.

MAIN OUTCOMES MEASURES

Interval MRI results, histopathology, and immunohistochemistry.

RESULTS

We present radiographic and histopathologic confirmation of the malignant nature of this extremely rare lesion. We also document its rapid response after radiosurgery as further indication of the malignant nature of this lesion.

CONCLUSION

Early and complete resection of internal auditory canal masses with atypical clinical courses suggestive of malignancy is the best initial option to treat these tumors with the understanding that further treatment with radiation or chemotherapy is essential.