title: Natural history of a medulloblastoma: 30 months of wait and see in a child with a cerebellar incidentaloma.
abstract: BACKGROUND
  With the increasing use of neuroimaging studies, the discovery of incidental neoplastic lesions is becoming more frequent. However, standard procedures are lacking, and little is known about their optimal management.
  
  
  METHODS
  We here present the case of a boy with a cerebellar mass incidentally discovered on a CT scan performed after head trauma. In another scan performed after another incident of head trauma 14 months earlier, the lesion could be seen after retrospective examination. In view of the asymptomatic clinical and stable radiological status and the presumed diagnosis of a low-grade glioma, a watch-and-wait strategy was elected. After clinical and radiological progression was observed, the tumour was resected, 2½ years after the initial imaging study. Histological evaluation revealed a WNT pathway-activated classical medulloblastoma.
  
  
  CONCLUSIONS
  To our knowledge, this is the first description of such a long natural history and pre-symptomatic period of a medulloblastoma. The long period of stability followed by a period of accelerated tumour growth is compatible with increasing biological aggressiveness, possibly related to the stepwise accumulation of genetic changes.
authors.affiliation: Department of Oncology, University Children's Hospital, 8032, Zurich, Switzerland.
authors.forename: Ulrike B
authors.initials: UB
authors.lastname: Zeilhofer
authors.affiliation: Department of Diagnostic Imaging, University Children's Hospital, 8032, Zurich, Switzerland.
authors.forename: Ianina
authors.initials: I
authors.lastname: Scheer
authors.affiliation: Department of Neuroradiology, University of Wuerzburg, 97080, Wuerzburg, Germany.
authors.forename: Monika
authors.initials: M
authors.lastname: Warmuth-Metz
authors.affiliation: Institute of Neuropathology, University Hospital Zurich, 8091, Zurich, Switzerland.
authors.forename: Elisabeth J
authors.initials: EJ
authors.lastname: Rushing
authors.affiliation: Institute of Neuropathology, University of Bonn, 53105, Bonn, Germany.
authors.forename: Torsten
authors.initials: T
authors.lastname: Pietsch
authors.affiliation: Department of Neurology, University Children's Hospital, 8032, Zurich, Switzerland.
authors.forename: Eugen
authors.initials: E
authors.lastname: Boltshauser
authors.affiliation: Department of Oncology, University Children's Hospital, 8032, Zurich, Switzerland.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Grotzer
authors.affiliation: Department of Oncology, University Children's Hospital, 8032, Zurich, Switzerland. nicolas.gerber@kispi.uzh.ch.
authors.forename: Nicolas U
authors.initials: NU
authors.lastname: Gerber
mesh_terms: D002528:Cerebellar Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D002648:Child; D018450:Disease Progression; D006801:Humans; D033162:Incidental Findings; D008279:Magnetic Resonance Imaging; D008297:Male; D008527:Medulloblastoma / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D014057:Tomography, X-Ray Computed; D057832:Watchful Waiting
keywords: Brain neoplasms; Cancer; Child; Incidental findings; Medulloblastoma; Radiology