title: Prevalence and natural history of pineal cysts in adults.
abstract: OBJECTIVE
  We reviewed our experience with pineal cysts to define the natural history and clinical relevance of this common intracranial finding.
  
  
  METHODS
  The study population consisted of 48,417 consecutive patients who underwent brain MR imaging at a single institution over a 12-year interval and who were over 18 years of age at the time of imaging. Patient characteristics, including demographic data and other intracranial diagnoses, were collected from cases involving patients with a pineal cyst. We then identified all patients with pineal cysts who had been clinically evaluated at our institution and who had at least 6 months of clinical and imaging follow-up. All inclusion criteria for the natural history analysis were met in 151 patients.
  
  
  RESULTS
  Pineal cysts measuring 5 mm or larger in greatest dimension were found in 478 patients (1.0%). Of these, 162 patients were male and 316 were female. On follow-up MR imaging of 151 patients with pineal cyst at a mean interval of 3.4 years from the initial study, 124 pineal cysts remained stable, 4 increased in size, and 23 decreased in size. Cysts that were larger at the time of initial diagnosis were more likely to decrease in size over the follow-up interval (p = 0.004). Patient sex, patient age at diagnosis, and the presence of septations within the cyst were not significantly associated with cyst change on follow-up.
  
  
  CONCLUSIONS
  Follow-up imaging and neurosurgical evaluation are not mandatory for adults with asymptomatic pineal cysts.
authors.affiliation: Department of Neurosurgery, University of Michigan, Ann Arbor, Michigan 48109-5338, USA.
authors.forename: Wajd N
authors.initials: WN
authors.lastname: Al-Holou
authors.forename: Samuel W
authors.initials: SW
authors.lastname: Terman
authors.forename: Craig
authors.initials: C
authors.lastname: Kilburg
authors.forename: Hugh J L
authors.initials: HJ
authors.lastname: Garton
authors.forename: Karin M
authors.initials: KM
authors.lastname: Muraszko
authors.forename: William F
authors.initials: WF
authors.lastname: Chandler
authors.forename: Mohannad
authors.initials: M
authors.lastname: Ibrahim
authors.forename: Cormac O
authors.initials: CO
authors.lastname: Maher
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D001927:Brain Diseases / Q000453:epidemiology* / Q000473:pathology*; D003560:Cysts / Q000453:epidemiology* / Q000473:pathology*; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010870:Pineal Gland / Q000473:pathology*; D015995:Prevalence; D055815:Young Adult