title: Abscess within a brain metastasis.
abstract: BACKGROUND
  Neoplastic metastases to the cerebellum are a frequent complication in patients with carcinoma. However, the co-existence of an abscess within a CNS metastasis is a rare event.
  
  
  METHODS
  We report the case of a 79-year-old woman with two cerebellar abscesses within metastatic lesions in the cerebellum. She presented with a rapidly progressing syndrome characterized by elevated intracranial pressure and cerebellar findings.
  
  
  RESULTS
  At surgery, a purulent exudate within discrete metastatic tumours was identified. Pathological and microbiological examinations confirmed the coexistence of an abscess within a metastatic carcinoma.
  
  
  CONCLUSIONS
  The radiological diagnosis o f intracranial abscesses and metastases can be non-specific and brain imaging may not reliably identify both processes when they coexist. Furthermore, brain metastases often contain liquefied material which can be mistaken for tissue necrosis rather than an infectious process. It is important to be aware that a brain metastasis can also be infected. Therefore, acquisition of lesional tissue for both pathological and microbiological examinations is essential for accurate diagnosis and to direct optimal therapy in situations where the intracranial lesion could be either an abscess or a metastatic deposit.
authors.affiliation: Division of Neurosurgery, Toronto Hospital, University of Toronto, Canada.
authors.forename: W P
authors.initials: WP
authors.lastname: Ng
authors.forename: A
authors.initials: A
authors.lastname: Lozano
mesh_terms: D000368:Aged; D001921:Brain / Q000000981:diagnostic imaging / Q000473:pathology; D001922:Brain Abscess / Q000473:pathology*; D001932:Brain Neoplasms / Q000556:secondary*; D005260:Female; D006801:Humans; D014057:Tomography, X-Ray Computed