A Case of Pulmonary Hydatid Cyst Misdiagnosed as Encysted Effusion

Echinococcosis or hydatid disease is caused by larvae of the tapeworm Echinococcus. In cystic echinococcosis, humans are an accidental host and are usually infected by handling an infected dog. The liver and lungs are the most frequently involved organs. Pulmonary disease appears to be more common in younger individuals. Although most patients are asymptomatic, some may occasionally expectorate the contents of the cystor develop symptoms related to compression of the surrounding structures. Other symptoms of hydatid disease can result from the release of antigenic material andsecondary immunological reactions that develop from cyst rupture.