title: MRI of medulloblastoma in adults.
abstract: Medulloblastoma has variable appearances on MRI in both children and adults. Adults are more likely to have heterogeneous cerebellar hemisphere tumours, and this is thought to be related to the greater prevalence of desmoplastic tumours in adulthood. Few studies have addressed the MRI features of adult medulloblastoma and the specific characteristics of desmoplastic and classic tumours have not been analysed. Our aim was to analyse the imaging characteristics of desmoplastic (DM) and classic (CM) medulloblastomas in adult. We retrospectively studied preoperative MRI of six men and three women, median age 33 years, range 23-53 years, with pathologically proved medulloblastomas. There were six (67%) with DM. The tumour was in the cerebellar hemisphere in eight patients (89%), including the three with CM, one of which was bilateral. All tumours were heterogeneous, giving predominantly low or isointense signal on T1- and isointense signal on T2-weighted images. Cystic or necrotic areas in all patients were particularly visible on T2-weighted images. Contrast enhancement was absent in one DM and varied from slight to intense in eight (three CM), homogeneous in one DM and patchy in seven. All tumours extended to the surface of the cerebellum and two had well-defined margins. MRI does not allow a clear distinction between DM and CM in adults.
authors.affiliation: Department of Neurology, Universidade Federal de São Paulo Rua Botucatu 740, SP 04023-900, Sao Paulo, Brazil. suzana@neuro.epm.br
authors.forename: S M F
authors.initials: SM
authors.lastname: Malheiros
authors.forename: H
authors.initials: H
authors.lastname: Carrete
authors.forename: J N
authors.initials: JN
authors.lastname: Stávale
authors.forename: A J
authors.initials: AJ
authors.lastname: Santos
authors.forename: L R R
authors.initials: LR
authors.lastname: Borges
authors.forename: I F
authors.initials: IF
authors.lastname: Guimarães
authors.forename: M P
authors.initials: MP
authors.lastname: Pelaez
authors.forename: C M R
authors.initials: CM
authors.lastname: Franco
authors.forename: A A
authors.initials: AA
authors.lastname: Gabbai
mesh_terms: D000328:Adult; D001931:Brain Mapping; D002528:Cerebellar Neoplasms / Q000145:classification / Q000175:diagnosis* / Q000503:physiopathology; D005260:Female; D006801:Humans; D007089:Image Enhancement; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D008297:Male; D008527:Medulloblastoma / Q000145:classification / Q000175:diagnosis* / Q000503:physiopathology; D008875:Middle Aged; D012189:Retrospective Studies