Note: This case has been tagged as "legacy" as it no longer meets image preparation and/or other case publication guidelines.
From the case:
Pulmonary Langerhans cell histiocytosis
Download
Info

The upper zones demonstrate coarsening of the pulmonary parenchymal markings with focal lucencies suggesting cystic spaces.
From the case:
Pulmonary Langerhans cell histiocytosis
Download
Info

CT demonstrates irregular lucencies/cystic spaces most marked in the upper zones.
Case Discussion
I believe this case was shown to be pulmonary Langerhans cell histiocytosis although no additional information is available.
Case courtesy of Dr Laura Jimenez Juan.