title: Serial volumetric assessment of the natural history and growth pattern of incidentally discovered meningiomas.
abstract: OBJECTIVE
  Due to advances in neuroimaging and the increasing use of imaging to screen for brain disease ("brain checkups"), meningiomas are now often detected as an incidental finding. The natural history of these asymptomatic meningiomas remains unclear, however. In this study, the authors investigated the natural history and growth pattern of incidentally detected meningiomas using serial volumetric assessment and regression analysis.
  
  
  METHODS
  In 70 patients with incidentally discovered meningiomas who underwent follow-up for longer than 1 year, tumor volumes were calculated volumetrically at each follow-up visit, and tumor growth was determined. In patients with tumor growth, regression analysis was performed to determine the pattern of growth.
  
  
  RESULTS
  Forty-four tumors exhibited growth and 26 did not. In a regression analysis, 16 of the tumors that grew followed an exponential growth pattern and 15 exhibited linear growth patterns. The presence of calcification was the only imaging characteristic that significantly distinguished the group with tumor growth from that without, although no radiological characteristics significantly distinguished the exponential growth group from the linear growth group. Two patients with obvious tumor growth underwent surgical removal and the pathological specimens extracted showed a high proliferative potential.
  
  
  CONCLUSIONS
  The authors found that incidentally discovered meningiomas did not always follow an exponential growth pattern but often exhibited more complex patterns of growth. Serial monitoring of tumor volumes and regression analysis may reveal the growth pattern of incidental meningiomas and provide information useful for determining treatment strategy.
authors.affiliation: Department of Neurosurgery, Osaka University Graduate School of Medicine, Suita City, Osaka, Japan.
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Hashiba
authors.forename: Naoya
authors.initials: N
authors.lastname: Hashimoto
authors.forename: Shuichi
authors.initials: S
authors.lastname: Izumoto
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Suzuki
authors.forename: Naoki
authors.initials: N
authors.lastname: Kagawa
authors.forename: Motohiko
authors.initials: M
authors.lastname: Maruno
authors.forename: Amami
authors.initials: A
authors.lastname: Kato
authors.forename: Toshiki
authors.initials: T
authors.lastname: Yoshimine
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001932:Brain Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D033162:Incidental Findings; D008279:Magnetic Resonance Imaging; D008297:Male; D008579:Meningioma / Q000000981:diagnostic imaging / Q000473:pathology*; D008875:Middle Aged; D011859:Radiography; D012044:Regression Analysis; D047368:Tumor Burden