title: Primary central nervous system lymphoma: is absence of intratumoral hemorrhage a characteristic finding on MRI?
abstract: BACKGROUND
  Previous studies have shown that intratumoral hemorrhage is a common finding in glioblastoma multi-forme, but is rarely observed in primary central nervous system lymphoma. Our aim was to reevaluate whether intratumoral hemorrhage observed on T2-weighted imaging (T2WI) as gross intratumoral hemorrhage and on susceptibility-weighted imaging as intratumoral susceptibility signal can differentiate primary central nervous system lymphoma from glioblastoma multiforme.
  
  
  METHODS
  A retrospective cohort of brain tumors from August 2008 to March 2013 was searched, and 58 patients (19 with primary central nervous system lymphoma, 39 with glioblastoma multiforme) satisfied the inclusion criteria. Absence of gross intratumoral hemorrhage was examined on T2WI, and an intratumoral susceptibility signal was graded using a 3-point scale on susceptibility-weighted imaging. Results were compared between primary central nervous system lymphoma and glioblastoma multiforme, and values of P < 0.05 were considered significant.
  
  
  RESULTS
  Gross intratumoral hemorrhage on T2WI was absent in 15 patients (79%) with primary central nervous system lymphoma and 23 patients (59%) with glioblastoma multiforme. Absence of gross intratumoral hemorrhage could not differentiate between the two disorders (P = 0.20). However, intratumoral susceptibility signal grade 1 or 2 was diagnostic of primary central nervous system lymphoma with 78.9% sensitivity and 66.7% specificity (P < 0.001), irrespective of gross intratumoral hemorrhage.
  
  
  CONCLUSIONS
  Low intratumoral susceptibility signal grades can differentiate primary central nervous system lymphoma from glioblastoma multiforme. However, specificity in this study was relatively low, and primary central nervous system lymphoma cannot be excluded based solely on the presence of an intratumoral susceptibility signal.
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Sakata
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Okada
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Yamamoto
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Mitsunori
authors.initials: M
authors.lastname: Kanagaki
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Yasutaka
authors.initials: Y
authors.lastname: Fushimi
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Toshiki
authors.initials: T
authors.lastname: Dodo
authors.affiliation: Department of Neurosurgery, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Arakawa
authors.affiliation: Department of Neurosurgery, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Jun C
authors.initials: JC
authors.lastname: Takahashi
authors.affiliation: Department of Neurosurgery, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Susumu
authors.initials: S
authors.lastname: Miyamoto
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Kaori
authors.initials: K
authors.lastname: Togashi
keywords: glioblastoma multiforme; magnetic resonance imaging; primary central nervous system lymphoma