Sporadic schwannomas and neurofibromas

Clinical vignette
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By Herbert B Newton MD

Vestibular schwannoma. Patient A.L. was a 44-year-old male with an unremarkable past medical history, who developed episodes of dizziness, tinnitus, and mild left-sided hearing loss. The symptoms presented over several months and were slowly progressive. The initial neurologic examination was unremarkable, and presented as normal. No stigmata of neurofibromatosis type 1 were present. Audiometry revealed a mild degree of hearing loss on the left side. An MRI scan demonstrated an enhancing mass 1 to 1.5 cm in diameter in the left cerebellopontine angle, with a tail that entered the internal auditory canal. The tumor was diagnosed as a vestibular schwannoma and the patient was transferred to the operating room. A suboccipital approach was used to expose the tumor. The cochlear division of cranial nerve VIII was draped over the mass; the mass was attached to the vestibular division of VIII. After the mass was dissected away from the vestibular division, the tumor was removed piecemeal, with preservation of cranial nerve VII. After surgery the patient did well, with some preservation of left-sided hearing and only mild left facial weakness. The facial weakness improved after several months. Follow-up MRI scans have remained free of recurrent tumor.

Trigeminal schwannoma. Patient L.D. was a 39-year-old male with an unremarkable past medical history, who initially noted severe, brief, electric shock-like pains on the right side of his face. The pain would last for 5 seconds to 10 seconds and then fade away quickly. An evaluation in a local emergency room demonstrated numbness on the right side of the face affecting the V2-3 distribution. Although the patient complained of numbness and paraesthesias of the tongue and buccal mucosa, sensation was normal. After an evaluation to rule out a stroke, the patient was given an MRI scan of the brain. The MRI showed an enhancing mass in the right Meckel cave region, consistent with a trigeminal schwannoma or meningioma. The patient was placed on carbamazepine 200 mg twice per day, with improvement of the neuralgic pain. The lesion was removed using a right temporal craniotomy and an approach that included drilling through the lateral sphenoid wing. The trigeminal ganglion had to be sacrificed to completely remove the tumor, a schwannoma. The patient developed a postoperative dysesthetic pain syndrome after surgery. Follow-up scans have remained free of residual or recurrent tumor. The pain syndrome has responded well to carbamazepine and amitriptyline. Recently, the patient has returned to full-time employment.

In This Article

Introduction
Historical note and nomenclature
Clinical manifestations
Clinical vignette
Etiology
Pathogenesis and pathophysiology
Epidemiology
Prevention
Differential diagnosis
Diagnostic workup
Prognosis and complications
Management
Pregnancy
Anesthesia
References cited
Contributors