Posterior cranial fossa tumors in young adults.

OBJECTIVE/HYPOTHESIS: This retrospective study presents our experience on the posterior cranial fossa tumors in young adults during the past 15 years.

METHODS: From 1991 to 2005, 16 (0.8%) of 2,091 young adults (range, 16-29 years) with dizziness/vertigo, hearing loss, or tinnitus were diagnosed with posterior fossa tumor. Each patient underwent a battery of audiovestibular tests and image study.

RESULTS: Audiometry revealed sensorineural hearing loss in 12 patients (75%). Spontaneous nystagmus was disclosed in eight patients (50%), consisting of bilateral gaze nystagmus in five, unilateral gaze nystagmus in two, and downbeat nystagmus in one. Electronystagmographic examination displayed abnormal eye tracking test in 75% and abnormal optokinetic nystagmus test in 81% of cases. Magnetic resonance imaging scan demonstrated space-occupying lesions at the cerebellopontine angle in 11, cerebellum in two, brainstem in two, and jugular fossa in one. Diagnoses consisted of vestibular schwannoma and neurofibromatosis II in eight patients (50%), glial neoplasm (including astrocytoma, ependymoma, glioma) in four patients (25%), epidermoid cyst in three patients, and glomus jugulare tumor in one patient. At study close, excluding one lost patient, three patients died as a result of recurrent or residual tumor at the primary site. Restated, 12 of 15 (80%) patients were alive.

CONCLUSIONS: Unlike predominant medulloblastoma in children, the most frequent posterior fossa tumor in young adults is vestibular schwannoma and neurofibroma. However, the second most frequent one in young adults is glial neoplasm as opposed to meningioma in adults.