A rare cause of pleural effusion: ruptured primary pleural hydatid cyst.

Hydatidosis is an endemic parasitic disease in Mediterranean countries, often caused by the dog tapeworm Echinococcus granulosus. The disease predominantly affects the liver (60-70%) and lungs (30%), and the surgical management is considered as the gold standard for treatment. Besides anaphylactic reactions, the most frequent complication of the hydatid disease is rupture into neighbouring structures, often affecting the bronchi, gastrointestinal tract and peritoneal/pleural cavities, according to its location. Primary pleural hydatidosis is an extremely rare entity and we present a ruptured pleural hydatid cyst with unusual location.