RESUMEN
INTRODUCTION: MacLeod syndrome, also known as Swyer-James syndrome, is a rare syndrome characterized by unilateral lung hyperlucency. It is a form of constrictive bronchiolitis which is caused by repeated acute bronchiolitis and/or pulmonary infections during infancy. CASE REPORT: The patient was a 26-year-old man who had had a first left pneumothorax at the age of 21. He smokes tobacco. When he was 1-year-old he had experienced repeated episodes of acute bronchiolitis. At age 26, he suffered from a second left pneumothorax which was wrongly diagnosed as a recurrent drain-resistant pneumothorax. Misdiagnosed, he underwent a chemical pleurodesis during thoracoscopy. As a hyperlucency remained in the left upper part of the lung on chest X-ray, further investigations were undertaken and a diagnosis of MacLeod syndrome was made. CONCLUSIONS: MacLeod syndrome is rare. It can be associated with pneumothorax which can be a source of misdiagnosis and error in the management of these patients. Therefore, the diagnostic criteria and therapeutic indications are reiterated. The probable mechanism of association between pneumothorax and Macleod syndrome is also discussed.