Fig. 4.

Progressive changes of a lung adenocarcinoma associated with a cystic airspace in a 60-year-old woman. (a) Axial low-dose CT shows an 8-mm cystic airspace with thin irregular non-solid wall in the upper left lobe (arrow). (b) One year later the lesion has increased in size to 12 mm and 2 years later, (c) a consistent irregular thickening with the development of solid components along the wall was evident (arrowhead). The histologic diagnosis was lung adenocarcinoma. This kind of presentation is usually slow growing on serial low-dose CT scans and the diagnosis of lung cancer is suggested by the circumferential wall thickening of the cystic airspaces; with tumor growth, airspaces size could increase, decrease or remain unchanged