A hydatid cyst
, cystic echinococcosis or hydatid disease, is a parasitic disease caused by tapeworm
eggs, Echinococcus granulosus. It is transmitted by ingestion of food contaminated with the feces of an infected dog, itself infected after eating viscera of an infected herbivore
. Once the egg hatches in the human stomach, the embryo migrates to the liver
and can go to the lungs, and even more rarely other organs and form a hydatid cyst. A hydatid cyst is often asymptomatic until the occurrence of a complication
, including its rupture which can be very serious. The cyst may be identified by an X-ray
or ultrasound. Once hydatidosis is identified, it should be treated by surgery or by a technique called needle aspiration.