An unusual mucous cyst of the lung.

A 68-year-old woman presented with a multilocular mucous cyst of the lung. At operation numerous seedling cysts were present on the parietal pleura, and the appearances strongly resembled those found in pseudomucinous cystadenoma of the ovary. The histological features suggested that the lesion was an unusual benign mucous cyst of the bronchus. After lobectomy and removal of pleural masses the patient has remained free from recurrence for five years.