Report a rare case of pulmonary hydatid cyst which present as massive pleural effusion

Common cause of massive pleural effusions (MPE) are malignancy, tuberculosis and parapneumonic effusion,. Parasitic infections are very rare causes of (MPE). Echinococcosis or hydatid disease is a major public health problem in poor hygienic country in the world. The liver is most common organ involved and lungs are the secound most frequently involved organs. Pulmonary hydatid cyst appears to be more common in younger individuals. Echinococcus granulosus is most common type and Echinococcus multilocularis hydatid cyst causes alveolar hydatid cyst, which accounts for <5%of all cases of hydatid disease of liver and less frequently cause of lung cyst. Here, we present an unusual and very rare case of echinococcosis pulmonary hydatid cysts mimicking and present as (MPE) with delay diagnosis. After antero-lateral thoracotomy. Diagnosis of hydatid cyst confirmed, patient was discharged with good condition.