Extradural dumbbell schwannoma of the hypoglossal nerve: a case report with review of the literature.

Background: Dumbbell-shaped schwannomas of the hypoglossal nerve are very rare. This report concerns a case with an extradural, dumbbell-shaped hypoglossal schwannoma extending both intra- and extracranially.

Methods: A 25-year-old woman presented with a right hypoglossal palsy. Imaging revealed a dumbbell-shaped tumor with considerable compression and medial displacement of the medulla oblongata, diagnosed as a hypoglossal schwannoma. The tumor mass extended extracranially to the parapharyngeal space through the enlarged hypoglossal canal. The tumor was partially excised by a right far-lateral suboccipital approach and the tumor was found to be predominantly extradural with minimal intradural extension. A histopathologic diagnosis of schwannoma was made.

Conclusions: This case emphasizes the importance of recognizing this extradural variant of schwannoma. Staged extracranial and intracranial approaches to these tumors may be necessary.