Primary malignant melanoma of the cerebellopontine angle: a diagnostic dilemma: case report.

Abstract

To present a rare case of a primary malignant melanoma of the central nervous system presenting as a cerebellopontine angle (CPA) tumor and to delineate aspects of the clinical presentation and magnetic resonance imaging scan characteristics that may suggest this unusual condition. The clinical presentation consisted of a short duration of right-sided sensorineural hearing loss, facial weakness, and ataxia in a previously healthy man. Brain magnetic resonance imaging scans showed a right-sided CPA tumor exhibiting shortening of T1 and T2 relaxation times, but overall neuroradiological features were not consistent with any commonly occurring CPA tumors. Gross total excision of the lesion was accomplished via a right suboccipital craniectomy. Histological examination revealed a malignant melanoma. A detailed search excluded extracranial primary melanoma. Correlation of clinical and imaging findings offer the most important clues in the diagnosis of such unusual primary malignant tumors of the CPA. A history of rapid onset of audiovestibular symptoms, presence of facial palsy, and shortening of T1 and T2 relaxation times on magnetic resonance imaging scans should arouse the clinician's suspicions.