Ruptured Pulmonary Hydatid Cyst with Multiple Small Bronchopleural Fistula Formations: A Case Report

Hydatid disease is a zoonosis caused by Echinococcus granulosus. It manifests as cystic lesions, most commonly found in the liver and lungs, and rarely in other parts of the body. The disease occurs when a human host accidentally ingests contaminated food containing eggs from canine waste products. Since the clinical characteristics of this disease are nonspecific, radiological investigations play a crucial role in diagnosis. Diagnostic challenges arise due to atypical imaging features of complicated hydatid cysts. A 40-year-old female patient presented with fever, breathlessness, chest pain, and an unproductive cough persisting for eight days. Upon examination, she was in hypovolaemic shock, and an intercostal drainage tube had been inserted in the left sixth intercostal space. The chest radiograph revealed a dense, homogeneous opacity in the left hemithorax, partially compressing the left lung medially. An High-resolution Computed Tomography (HRCT) thorax showed a thick-walled cavity with an air-fluid level and layered membranes in the dependent part of the cavity, indicating a water lily sign in the left lower lobe of the lung, suggesting a ruptured hydatid cyst. The patient underwent cystectomy with suturing of a small bronchopleural fistula. Computed Tomography (CT) is the preferred imaging modality, especially for assessing associated complications and ruling out differentials in cases of ruptured pulmonary hydatid cysts.