title: "Flow-void" sign at MR imaging: a rare finding of extracranial head and neck schwannomas.
abstract: The authors present two cases of extracranial head and neck schwannomas that exhibited the "flow-void" sign at MR imaging. In the described cases, MR images showed intratumoral signal voids, which corresponded to dilated vessels. Dynamic contrast-enhanced CT also demonstrated dilated vessels within the tumors on the arterial phase and tumor parenchymal enhancement on the delayed phase. Histopathologic examinations of excised specimens revealed thin-walled, dilated abnormal vessels with or without hyaline degeneration. Schwannoma should be considered when MR images demonstrate the "flow-void" sign in extracranial head and neck tumors.
authors.affiliation: Department of Radiology, Gifu University School of Medicine, Gifu, Japan. hkato@gifu-u.ac.jp
authors.forename: Hiroki
authors.initials: H
authors.lastname: Kato
authors.forename: Masayuki
authors.initials: M
authors.lastname: Kanematsu
authors.forename: Keisuke
authors.initials: K
authors.lastname: Mizuta
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Aoki
authors.forename: Bunya
authors.initials: B
authors.lastname: Kuze
authors.forename: Takatoshi
authors.initials: T
authors.lastname: Ohno
authors.forename: Koji
authors.initials: K
authors.lastname: Oshima
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Hirose
mesh_terms: D000328:Adult; D001932:Brain Neoplasms / Q000175:diagnosis; D006258:Head and Neck Neoplasms / Q000175:diagnosis*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009442:Neurilemmoma / Q000175:diagnosis*; D035583:Rare Diseases / Q000175:diagnosis; D055815:Young Adult