title: Invasive thymoma metastatic to the cavernous sinus.
abstract: BACKGROUND
  Thymomas are typically benign tumors of thymic epithelium. Metastases to distal sites, particularly intracranial locations, are extremely rare. Herein, we present the third case of thymoma and the second invasive thymoma to metastasize to the cavernous sinus, adjacent to the pituitary.
  
  
  METHODS
  A 41-year-old female patient presented with headaches, stuffy nose, and drooping of the right face. A magnetic resonance imaging scan revealed a complex, multilobulated mass centered upon the right cavernous sinus. The mass was removed via transsphenoidal surgery, and histopathological investigation confirmed the diagnosis of metastatic thymoma. A positron emission tomography-computed tomography scan demonstrated a large anterior mediastinal mass. A biopsy confirmed the diagnosis of invasive thymoma morphologically identical to the World Health Organization type B2 sellar region metastasis.
  
  
  CONCLUSIONS
  Although rare, thymomas can metastasize to the central nervous system. Our case is the second invasive thymoma to metastasize to the cavernous sinus, adjacent to the pituitary.
authors.affiliation: Divisions of Pathology, St. Michael's Hospital, Toronto, Ontario, Canada ; Department of Neurosurgery, St. Michael's Hospital, Toronto, Ontario, Canada.
authors.forename: F
authors.initials: F
authors.lastname: Nassiri
authors.forename: B W
authors.initials: BW
authors.lastname: Scheithauer
authors.forename: D J
authors.initials: DJ
authors.lastname: Corwin
authors.forename: H G
authors.initials: HG
authors.lastname: Kaplan
authors.forename: M
authors.initials: M
authors.lastname: Mayberg
authors.forename: M D
authors.initials: MD
authors.lastname: Cusimano
authors.forename: F
authors.initials: F
authors.lastname: Rotondo
authors.forename: K
authors.initials: K
authors.lastname: Kovacs
keywords: Cancer; immunohistochemistry; metastatic tumor; pathology; sellar metastases; thymoma