Late-Onset Intracranial Melanotic Schwannoma of the Cerebellopontine Angle: Case Report and Review of the Literature.

Melanotic schwannoma is a rare malignant tumor of nerve sheaths characterized by melanin-producing cells. It is mostly localized in the posterior roots of spinal nerves or sympathetic ganglia whereas the intracranial localizations are less common. The aim of this study is to describe a case of sporadic melanotic schwannoma of the right cerebellopontine angle, including a literature review of the topic. This is the case of a 79-year-old woman who presented with right-sided hearing loss and vertigo. Magnetic resonance imaging (MRI) of the brain revealed an 8 × 6 mm lesion at the level of the right cerebellar peduncle, hyperintense on T1-weighted sequences. A gross total resection of the lesion was performed through a retrosigmoid approach. The histological and immunohistochemical exams were consistent with a malignant melanotic schwannoma. Research was conducted using Pubmed and a reference list. Only melanotic schwannomas with intracranial localizations were considered. Twenty-nine articles were included in this review, reporting a total number of 32 cases of intracranial melanotic schwannomas. The treatment of choice is the complete surgical excision of the neoplasm; adjuvant radiotherapy correlates with lower rates of recurrence and metastasis. Our case represents the latest onset of an intracranial melanocytic schwannoma with a clinical course similar to a conventional eighth cranial nerve schwannoma.