Unilateral hyperlucent lung in a patient with mitral stenosis

Rheumatic heart disease remains a major problem in the developing word, especially in the tropical countries. In this case report we describe a patient with rheumatic mitral stenosis who was referred to our Chest Clinic for exclusion of asthma as she had no improvement following balloon mitral valvuloplasty. Chest radiograph revealed a unilateral hyperlucent lung. Although initially a diagnosis of upper airway obstruction secondary to giant left atrium was thought, further investigations revealed the cause to be MacLeod's syndrome. We discuss the pathological and radiological manifestations of the MacLeod's syndrome, and also discuss the differential diagnosis of unilateral hyperlucent lung, especially in a patient with mitral stenosis. We also highlight the historical controversies associated with the MacLeod's or Swyer-James syndrome.