Case report: A 13 year old boy had a seven day history of chest pain and dyspnea. His right hemithorax was immobile with abolished breathing sounds. Initial chest X-ray revealed a right tension pneumothorax. A chest tube was inserted and the right lung re-expanded. However, despite two intrapleural injections of tetracyclin, the pneumothorax reappeared. Lung CT scan showed an intraparechymal cyst in the posterior part of the right upper lobe. Lobectomy was performed and histological study confirmed the diagnosis of type I cystic adenomatoid malformation of the lung. Two months after surgery, clinical and radiological examinations were normal.
Conclusion: Spontaneous pneumothorax, as the initial manifestation of cystic adenomatoid malformation of the lung, is rare (three cases reported in children beyond the neonatal period, and two in adults). CT scan features correlate well with the pathologic features. Because of the risk of recurrent pulmonary infections and malignancy change, removal of the cystic lesions is advisable.