Primary melanocytic tumor of the cerebellopontine angle mimicking a vestibular schwannoma: Case report

OBJECTIVE: The majority of tumors of the cerebellopontine angle (CPA) are benign. We report the case of a primary malignant melanoma of the CPA that mimicked a vestibular schwannoma (acoustic neuroma). We discuss the differential diagnosis and prognosis of melanotic lesions at this location. CLINICAL PRESENTATION: A 49-year-old man presented with a 7-year history of unilateral deafness and a several month history of imbalance, intractable nausea and vomiting, as well as weight loss. A neurological work-up revealed a large tumor in the left CPA radiographically diagnosed as a vestibular schwannoma. INTERVENTION: A translabyrinthine approach revealed a pigmented, vascular neoplasm encasing vessels and cranial nerves of the left CPA. The tumor was subtotally resected, and a histopathological diagnosis of melanoma was made. The patient had no history of cutaneous melanoma and no other site of disease was ever discovered. CONCLUSION: This case most likely represents primary melanoma of the central nervous system that mimicked a vestibular schwannoma. The differential diagnosis of melanotic lesions of the CPA is discussed as are the prognostic implications of each diagnosis.