title: A rare intracranial tumor consisting of malignant anaplastic and papillary meningioma subtypes.
abstract: BACKGROUND
  Intracranial tumors with heterogeneous histopathology are a well-described pathologic entity. Pathologically, distinct tumors in direct contact with one another, also known as collision tumors are exceptionally rare, and collision between meningioma subtypes has not been previously described in the literature.
  
  
  METHODS
  A 79-year-old female with a history of breast carcinoma presenting with visual and motor deficits and imaging/intraoperative findings consistent with separate, distinct lesions. Histopathologic findings provided evidence for a collision between World Health Organization Grade III anaplastic and papillary meningioma.
  
  
  CONCLUSIONS
  We report a possible collision tumor between two separate meningioma subtypes based on the unique radiologic, intraoperative, and histopathologic findings. Submission of multiple pathologic specimens during surgical resection is key for accurate histopathologic diagnosis.
authors.affiliation: Department of Neurosurgery, Rush University Medical Center, Chicago, IL, USA.
authors.forename: Ryan B
authors.initials: RB
authors.lastname: Kochanski
authors.affiliation: Department of Neurosurgery, Rush University Medical Center, Chicago, IL, USA.
authors.forename: Nika
authors.initials: N
authors.lastname: Byrne
authors.affiliation: Department of Pathology, Rush University Medical Center, Chicago, IL, USA.
authors.forename: Leonidas
authors.initials: L
authors.lastname: Arvanitis
authors.affiliation: Department of Radiology, Rush University Medical Center, Chicago, IL, USA.
authors.forename: Sudeep
authors.initials: S
authors.lastname: Bhabad
authors.affiliation: Department of Neurosurgery, Rush University Medical Center, Chicago, IL, USA.
authors.forename: Richard W
authors.initials: RW
authors.lastname: Byrne
keywords: Anaplastic; collision tumor; meningioma; papillary