"Water-lily sign" as a rare finding of spinal hydatidosis.

Hydatid disease (HD) is a common parasitic infestation in some developing countries. Hydatid disease may affect many organs in the body, but the most affected are the liver and lungs. Hepatic and pulmonary HD is relatively easier to diagnose because of the frequency of pathognomic features and its order in the differential diagnosis list. When HD is located in uncommon sites, it is difficult to recognize even in endemic areas. The "water-lily sign" is a pathognomic sign for HD and mostly described especially after puncture or percutaneous treatment of the cyst. In this case, we observed the water-lily sign in spinal HD, which was not described before for spinal cases but for soft tissues.