title: Exophytic pilocytic astrocytoma of the brain stem in an adult with encasement of the caudal cranial nerve complex (IX-XII): presurgical anatomical neuroimaging using MRI.
abstract: We describe a rare case of adult pilocytic astrocytoma in which exophytic growth from the brain stem presented as a right cerebellopontine angle mass. An initial MRI examination using T2- and T1-weighted images without and with contrast suggested the diagnosis of schwannoma. Subsequent use of 3D CISS (three-dimensional constructive interference in steady state) and T1-weighted contrast-enhanced 3D MP-RAGE (three-dimensional magnetization prepared rapid acquisition gradient echo) sequences led to the diagnosis of an exophytic brain stem tumor, documented the precise relationships of the tumor to cranial nerve VIII, revealed encasement of cranial nerves IX-XII (later confirmed intraoperatively), and provided the proper basis for planning surgical management.
authors.affiliation: Department of Neuroradiology, Klinikum Grosshadern, Ludwig-Maximilians University, Marchioninistr. 15, 81377 Munich, Germany. indra.yousry@ikra.med.uni-muenchen.de
authors.forename: Indra
authors.initials: I
authors.lastname: Yousry
authors.forename: Alexander
authors.initials: A
authors.lastname: Muacevic
authors.forename: Vlad
authors.initials: V
authors.lastname: Olteanu-Nerbe
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Naidich
authors.forename: Tarek A
authors.initials: TA
authors.lastname: Yousry
mesh_terms: D000055:Accessory Nerve / Q000473:pathology; D000328:Adult; D001254:Astrocytoma / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery; D020295:Brain Stem Neoplasms / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery; D002530:Cerebellopontine Angle / Q000473:pathology; D003391:Cranial Nerves / Q000473:pathology*; D005260:Female; D005930:Glossopharyngeal Nerve / Q000473:pathology; D006801:Humans; D007002:Hypoglossal Nerve / Q000473:pathology; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging; D014630:Vagus Nerve / Q000473:pathology; D000159:Vestibulocochlear Nerve / Q000473:pathology