Ruptured pulmonary hydatid cyst (PHC) is an important clinical problem in endemic areas to echinococcal infection. Herein we present a rare case of ruptured PHC in an adolescent boy that was misdiagnosed as pulmonary tuberculosis in local health center. When sputum specimen was stained by acid-fast staining for detection of Mycobacterium tuberculosis, hooklets of Echinococcus granulosus were observed. A simple chest X-ray showed a multilobulated mass in the lower part of the left lung. Computed tomography scan verified existence of thick walled caviar lesion with irregular air-fluid level. The diagnosis was confirmed at the time of surgery. Misdiagnoses of PHC may even lead to irreparable damages. Therefore, accurate diagnosis is necessary to prevent severe complications.
Keywords: Echinococcus granulosus; Lung; Mycobacterium tuberculosis; Pulmonary hydatid cyst.