ABSTRACT
Intact pulmonary hydatid cysts are often discovered incidentally on chest X-rays (CXRs) as rounded opaque lesions with smooth borders. Cyst rupture and infection (complicated hydatid cyst) often change the radiologic appearance delaying diagnosis. Air bubble sign on computed tomography is recognized as a sign of high sensitivity and specificity in the diagnosis of complicated hydatid cysts when compared to other classical radiologic signs. Bronchoscopy is not a preferred investigation in patients with intact hydatid cysts but may have a major role in patients with complicated hydatid cysts with atypical presentation. In the present case series, we attempt to highlight the importance of the 揳ir bubble sign� and the identification of a whitish membrane at bronchoscopy in the diagnosis of complicated hydatid cysts.