[Diagnostic considerations in unilateral hyperlucency of the lung (Swyer-James-MacLeod Syndrome)].

Swyer-James-MacLeod Syndrome (SJMS) is considered to be a relatively uncommon and complex disease characterized by roentgenographic hyperlucency of one lung, lobe, or part of a lobe, due the pulmonary vascular structure and alveolar overdistension. It is sometimes associated with bronchiectasis. This syndrome seems to be an acquired disease that develops after viral bronchiolitis and/or viral pneumonia in early childhood. Microscopically, there is evidence of patchy bronchitis and bronchiolitis.SJMS is usually asymptomatic and discovered accidentally by chest radiography in a child with respiratory symptoms and should be differentiated from other causes of unilateral hyperlucency on chest radiography, such as those related to congenital bronchial and/or vascular abnormalities. Treatment includes early control of lung infections, as well as influenza and pneumococcal vaccination. Few reports of this syndrome in children have been published. We describe the case of a 12-year-old boy with unilateral hyperlucency of the lung and respiratory symptoms of acute pneumonia and discuss the main diagnostic features of this syndrome.