Pulmonary bulla in children represent interesting entities. Mostly congenital bronchopulmonary foregut malformations and acquired cysts like pneumatocoeles have also been described. We present a case of a 12 1/2 years old girl with acute onset respiratory distress symptoms harbouring a huge pulmonary cyst exhibiting mass effects, resulting in mediastinal deviation. Following initial workup, cyst excision was carried out which revealed presence of fungal hyphae that was susceptible to Fluconazole therapy post operatively. The case points out how a pulmonary cyst can present in older children with symptoms of respiratory distress and mass effects.