title: Azygos lobe without azygos vein as a sign of previous iatrogenic pneumothorax: two case reports.
abstract: BACKGROUND
  A spontaneous pneumothorax appears to be rarely seen in patients with an azygos lobe, although this normal variant is incidentally found on CT and chest X-ray. The displacement of the azygos vein from the azygos lobe to the paramediastinal position indicates previous pneumothorax.
  
  
  METHODS
  We report two patients (a 59 and a 27-year-old female) where the finding of an azygos lobe without an azygos vein proved to be a sign of previous iatrogenic pneumothorax.
  
  
  CONCLUSIONS
  Documentation of an azygos lobe without azygos vein is highly suggestive of a previous pneumothorax. This observation may indicate an iatrogenic cause, because of the possible protective effect of an azygos lobe to the occurrence of spontaneous pneumothorax.
authors.affiliation: Institut für Diagnostische und Interventionelle Radiologie sowie Nuklearmedizin, Tièchestrasse 99, Zurich, Switzerland.
authors.forename: Thomas
authors.initials: T
authors.lastname: Betschart
authors.forename: Gerhard W
authors.initials: GW
authors.lastname: Goerres
mesh_terms: D000328:Adult; D001401:Azygos Vein / Q000002:abnormalities* / Q000000981:diagnostic imaging; D002405:Catheterization, Central Venous / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008168:Lung / Q000002:abnormalities* / Q000000981:diagnostic imaging; D008875:Middle Aged; D011030:Pneumothorax / Q000209:etiology*; D011859:Radiography