title: Mucosal cysts in the paranasal sinuses: long-term follow-up and clinical implications.
abstract: BACKGROUND
  Although mucosal cysts in the paranasal sinuses (PSMCs) are commonly detected, the long-term follow-up studies of PSMCs are sparse. This study evaluated the natural course of PSMCs and identified risk factors for the disease progression.
  
  
  METHODS
  A total of 133 subjects with PSMCs who underwent health checkup including brain magnetic resonance imaging more than two times with an interval of ≥24 months between January 2000 and December 2009 were included. The characteristics of PSMCs were analyzed on the initial and follow-up images. Nasal symptoms, smoking status, and comorbid medical conditions were evaluated using structured questionnaires and medical records.
  
  
  RESULTS
  The mean follow-up duration was 40.38 months (range, 24.0-109.8 months). The mean size of PSMCs decreased from 15.07 to 12.73 mm. Only 8.3% of subjects showed an increase in size, whereas the size of cysts was decreased or unchanged in the remaining 91.7% of subjects. Six (4.5%) subjects complained of nasal symptoms during follow-up and subsequent sinusitis was developed in 3% of subjects. An increase in cyst size was associated with development of sinusitis (odds ratio = 45.375). Initial size of cysts >20 mm and bilateral location were significant risk factors for progression (p = 0.019 and p = 0.039, respectively).
  
  
  CONCLUSIONS
  The majority of PSMCs in this follow-up study were decreased or unchanged and most subjects were asymptomatic. Just observation is enough for most PSMCs. However, those who have a large cyst (>20 mm) or bilateral cysts at initial diagnosis were at risk for disease progression and should be regularly followed.
authors.affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Il Joon
authors.initials: IJ
authors.lastname: Moon
authors.forename: Sang-Wook
authors.initials: SW
authors.lastname: Kim
authors.forename: Doo Hee
authors.initials: DH
authors.lastname: Han
authors.forename: Jae Min
authors.initials: JM
authors.lastname: Shin
authors.forename: Chae-Seo
authors.initials: CS
authors.lastname: Rhee
authors.forename: Chul Hee
authors.initials: CH
authors.lastname: Lee
authors.forename: Yang-Gi
authors.initials: YG
authors.lastname: Min
mesh_terms: D000328:Adult; D000368:Aged; D048708:Cell Growth Processes; D003560:Cysts / Q000175:diagnosis / Q000453:epidemiology* / Q000473:pathology / Q000503:physiopathology*; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009092:Mucous Membrane / Q000473:pathology; D010254:Paranasal Sinus Diseases / Q000175:diagnosis / Q000453:epidemiology* / Q000473:pathology / Q000503:physiopathology*; D010256:Paranasal Sinuses / Q000000981:diagnostic imaging / Q000473:pathology*; D012307:Risk Factors; D012852:Sinusitis; D011795:Surveys and Questionnaires; D014057:Tomography, X-Ray Computed