title: Frontal recess cells: a rare cause of frontal sinus pneumocoele.
abstract: OBJECTIVE
  A pneumocoele is a pathologically expanding, air-containing paranasal sinus. Pneumocoeles are uncommon entities, with very few cases reported in the literature. The most plausible aetiological theory is that of a one-way valve effect allowing air into the sinus under increased pressure without pressure equilibration.
  
  
  METHODS
  Review of a frontal sinus pneumocoele caused by a type III frontal cell and intersinus septal cell.
  
  
  RESULTS
  We present a patient with chronic sinusitis who developed a pneumocoele of her left frontal sinus with erosion into her orbit. This patient was a habitual, chronic nose-blower with a large type III frontal cell adjacent to an intersinus septal cell.
  
  
  CONCLUSIONS
  We propose the new theory that, in our patient, such cells formed a one-way valve, causing air-trapping and pathological expansion of the frontal sinus. To our knowledge, there are no previously published cases that establish an association between large frontal cells and expansion of a pneumocoele.
authors.affiliation: Division of Otolaryngology, Department of Surgery, University of Alabama at Birmingham, AL 35294, USA.
authors.forename: J F
authors.initials: JF
authors.lastname: Dixon
authors.forename: B A
authors.initials: BA
authors.lastname: Woodworth
mesh_terms: D000328:Adult; D004646:Emphysema / Q000000981:diagnostic imaging / Q000209:etiology; D005260:Female; D005626:Frontal Sinus / Q000000981:diagnostic imaging* / Q000473:pathology; D006801:Humans; D009915:Orbit / Q000000981:diagnostic imaging*; D010254:Paranasal Sinus Diseases / Q000000981:diagnostic imaging* / Q000209:etiology; D012852:Sinusitis / Q000150:complications*; D014057:Tomography, X-Ray Computed