FIGURE 7.

a–f) Increase in cystic airspace size, presumed to occur due to check-valve mechanism. A small cyst-related lesion in the left lower lobe (b) of a 64-year-old female with a history of breast carcinoma. This lesion was present at the time of diagnosis of a T2aN3M1b adenocarcinoma in the right lower lobe (a); however, it was not acknowledged. Over the course of 18 months the size and wall thickness progressed significantly (c, d, f) and eventually the lesion showed a solid component posteriorly (e). No pathology was obtained due to extensive comorbidity.