title: Chondromyxoid fibroma of the mastoid facial nerve canal mimicking a facial nerve schwannoma.
abstract: Chondromyxoid fibroma of the skull base is a rare entity. Involvement of the temporal bone is particularly rare. We present an unusual case of progressive facial nerve paralysis with imaging and clinical findings most suggestive of a facial nerve schwannoma. The lesion was tubular in appearance, expanded the mastoid facial nerve canal, protruded out of the stylomastoid foramen, and enhanced homogeneously. The only unusual imaging feature was minor calcification within the tumor. Surgery revealed an irregular, cystic lesion. Pathology diagnosed a chondromyxoid fibroma involving the mastoid portion of the facial nerve canal, destroying the facial nerve.
authors.affiliation: Division of Neuroradiology, Department of Medical Imaging, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Thompson
authors.forename: Aditya
authors.initials: A
authors.lastname: Bharatha
authors.forename: Richard I
authors.initials: RI
authors.lastname: Aviv
authors.forename: Julian
authors.initials: J
authors.lastname: Nedzelski
authors.forename: Joseph
authors.initials: J
authors.lastname: Chen
authors.forename: Juan M
authors.initials: JM
authors.lastname: Bilbao
authors.forename: John
authors.initials: J
authors.lastname: Wong
authors.forename: Reda
authors.initials: R
authors.lastname: Saad
authors.forename: Sean P
authors.initials: SP
authors.lastname: Symons
mesh_terms: D000328:Adult; D002812:Chondroma / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D003937:Diagnosis, Differential; D005154:Facial Nerve / Q000473:pathology*; D005260:Female; D005350:Fibroma / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D006801:Humans; D008279:Magnetic Resonance Imaging; D008416:Mastoid / Q000294:innervation* / Q000601:surgery; D009442:Neurilemmoma / Q000175:diagnosis; D014057:Tomography, X-Ray Computed