Giant pulmonary hydatid cyst is usually encountered in adolescents and children who are older than 10 years. A relatively higher elasticity of the lung tissue allows rapid growth of cysts. We present a case of a 15-year-old male who was admitted with complaint of frequent and persistent dry cough for over a month. Computed tomographic scan revealed a giant cyst with thick enhancing rim and an "air bubble" sign. Diagnosis of giant hydatid cyst was confirmed by surgery and histopathological examination.
Keywords: Air bubble sign; echinococcus granulosus; giant pulmonary hydatid cyst; thoracic surgery.