<unk>   is a rare benign congenital malformation in which there is a fluid filled mass in the lungs.
Bronchogenic cyst
Tracheal diverticulum
Pulmonary cystic lymphangiectasis
Colloid cyst
Peritonsillar abscess
Mediastinal lipomatosis
Bronchopleural fistula
Pulmonary artery sarcoma