-Describe the imaging features of hydatid disease in rare anatomic locations and discuss its unusual complications. -Discuss the roles of US, CT, and MR imaging in the diagnosis of hydatid disease.

Hydatid disease is a worldwide zoonosis produced by the larval stage of the Echinococcus tapeworm. Although liver and lung are the most commonly involved organs, hydatid disease can occur in all viscera and soft tissues. In humans, hydatid disease involves the liver in approximately 75% of cases and the lung in 15%. Secondary involvement due to hematogenous dissemination may be seen in almost any anatomic location.

I. Life cycle of Echinonococcus granulosus: The life cycle consists of a definite host and an intermediate host ( Fig. 2 ). Sheep and other ruminants are intermediate hosts, whereas dogs and other carnivores are definitive hosts. Humans get secondarily infected by ingestion of food or drinks contaminated with dog feces containing the eggs of the worm. Free embryos enter the portal circulation through the gut wall and gets lodged in the liver parenchyma. A few of these enter the systemic circulation and get lodged...

Despite their rarity, being familiar with the spectrum of radiologic findings in unusual sites of hydatic disease is helpful to improve diagnostic accuracy.

S. Mghaieth; Tunis/TN - nothing to disclose B. Khaled; Nabeul/TN - nothing to disclose

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