A cylindrical extracranial cranial base neurinoma of the hypoglossal nerve: a rare tumor with a rare localization: case report.

Abstract

Neurinomas of the hypoglossal nerve are very rare. They are mostly located intracranially or combined intra- and extracranially, resulting in the so-called dumbbell shape. The isolated extracranial localization of the neurinoma of the hypoglossal nerve adjacent to the cranial base as described in this case report is extremely rare. The 23-year-old patient presented with recurring headaches. She had right-sided hypoglossal nerve palsy for approximately 5 to 6 years. Magnetic resonance imaging revealed an extracranial tumor with contact to the cranial base originating from the hypoglossal nerve. The tumor was extirpated surgically and verified histologically as a schwannoma of the hypoglossal nerve. Pathologies of the hypoglossal nerve as such are very rare within the clinical landscape. When a tumor occurs, its shape and location must be analyzed to establish whether, or by which approach, surgical removal is feasible. Although very unusual, the mere extracranial occurrence of a hypoglossal neurinoma at the cranial base should be considered a differential diagnosis.