title: Large cystic hypoglossal schwannoma with fluid-fluid level: a case report.
abstract: Hypoglossal schwannomas are rare skull base tumors. Furthermore, cystic hypoglossal schwannomas are extremely uncommon. We report the first case of a large cystic hypoglossal schwannoma with a fluid-fluid level. A 36-year-old woman presented with increased intracranial pressure and cerebellar signs without hypoglossal nerve palsy. Magnetic resonance imaging showed a predominantly cystic mass with a fluid-fluid level in the foramen magnum region extending into the hypoglossal canal. The intracranial tumor was largely removed via a midline suboccipital subtonsillar approach, leaving only a tiny residue in the hypoglossal canal. Histology confirmed a schwannoma with relative hypervascularity. Twenty months later, the tumor recurred and presented as a multicystic dumbbell-shaped lesion, extending intra- and extracranially through the enlarged hypoglossal canal. A complete resection of the intracranial and intracanalicular parts of the tumor was achieved with a small extracranial remnant treated by radiosurgery. Histology revealed a focal increased K(i)67 proliferative index. In this report, we discuss the possible reasons for the absence of hypoglossal nerve palsy and the potential mechanism of the formation of the fluid-fluid level, and we consider the treatment of this lesion.
authors.affiliation: Department of Neurosurgery, First Hospital of Jilin University, Changchun, China.
authors.forename: Wen-Chen
authors.initials: WC
authors.lastname: Li
authors.forename: Xin-Yu
authors.initials: XY
authors.lastname: Hong
authors.forename: Li-Ping
authors.initials: LP
authors.lastname: Wang
authors.forename: Peng-Fei
authors.initials: PF
authors.lastname: Ge
authors.forename: Shuang-Lin
authors.initials: SL
authors.lastname: Fu
authors.forename: Yi-Nan
authors.initials: YN
authors.lastname: Luo