ECHINOCOCCOSIS is uncommon in the continental United States1; because the disease is difficult to diagnose, the characteristic cysts of the cestode Echinococcus granulosus are often approached surgically without prior diagnosis and occasionally are ruptured. An Echinococcus cyst may be present in any organ of the body, but it is most frequently situated in the liver or the lung.1 Rupture or incision may result in the spillage of hydatid material, ie, detached germinal layer, brood capsules, and scolices, into the peritoneal or thoracic cavities and may result in an immediate anaphylactic reaction or in the long-term development of secondary cysts in contaminated sites.1 Several cases of traumatic or surgical rupture of hydatid cysts followed by secondary-cyst formation have been reported.2-5 Frequently, spillage followed attempts to aspirate the cysts. Dew6 stated that secondary-cyst formation is a common and constant risk to all patients with intra-abdominal hydatid cysts.