Intact bronchogenic cyst presenting as a lung mass provoking a pleural effusion: a rare presentation.

This case report describes a 49 year old woman with an intra-parenchymal bronchogenic cyst masked on chest x-ray examination by a pleural effusion. The cyst was intact. It is likely that the cyst provoked the pleural effusion by repetitive mechanical irritation of the pleura. At surgery, the cyst was removed and the pleural effusion drained without recurrence. The cyst was unilocular and measured 8.5 x 7.0 x 0.8 cm with a smooth and glistening lining. It was filled with approximately 300 ml of clear fluid. Microscopic examination confirmed the bronchogenic cyst. This is the first case of an intact intra-parenchymal bronchogenic cyst associated with a pleural effusion that was not due to rupture of the cyst, infection or malignancy.