Describe Vanishing lung syndrome.
Vanishing lung syndrome, also known as idiopathic giant bullous emphysema, is a rare disease characterized by giant emphysematous bullae. It is a rare radiological syndrome in which the lungs appear to be disappearing on X-ray. It  typically occurs in young, thin male smokers with large bullae in one or more upper lobes occupying at least one-third of the hemithorax. This syndrome is associated with significant morbidity and mortality.