title: Histological characteristics of incidentally-found growing meningiomas.
abstract: OBJECTIVE
  With the wider use of CT and MRI, many meningiomas are discovered as incidental findings during diagnostic work-up for unrelated symptoms. The majority shows no or minimal growth. The purpose of this study was to distinguish pathological features of incidentally-found growing meningiomas by comparing incidentally-found with symptomatic meningiomas.
  
  
  METHODS
  One hundred and thirty two consecutive non-recurrent surgically-treated meningiomas treated between 2005 and 2007 were divided into three categories: 19 incidentally-found growing meningiomas (IG), 50 incidentally-found meningiomas (I), and 63 symptomatic (S) meningiomas. The average follow-up period for the IG meningiomas was 3.7 years. Six out of 19 patients of the IG meningiomas became symptomatic during observation.
  
  
  RESULTS
  There is a significant difference of the incidence of WHO grades I, II, and III between all three groups (p=0.035). The incidence of WHO grades II and III in groups IG, I, and S were 26%, 2%, and 10%, respectively. We compare MIB-1 staining index between three groups: an average was 3.8% in IG, 1.3% in I, and 2.4% in S meningiomas.
  
  
  CONCLUSIONS
  Incidentally-found meningiomas need careful follow-up. One fourth of the meningiomas that showed signs of growing belonged to the atypical or malignant grade.
authors.affiliation: Department of Neurosurgery, Tokyo Women's Medical University, Tokyo, Japan.
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Kasuya
authors.forename: Osami
authors.initials: O
authors.lastname: Kubo
authors.forename: Koichi
authors.initials: K
authors.lastname: Kato
authors.forename: Boris
authors.initials: B
authors.lastname: Krischek
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008577:Meningeal Neoplasms / Q000737:chemistry / Q000473:pathology*; D008579:Meningioma / Q000737:chemistry / Q000473:pathology*; D008875:Middle Aged; D060787:Neoplasm Grading; D044767:Ubiquitin-Protein Ligases / Q000032:analysis
chemical_list: C513496:MIB1 ligase, human; D044767:Ubiquitin-Protein Ligases