In this article, the author describes the “hanging drop sign” to aid in the sonographic diagnosis of orbital cysticercus cysts. A cysticercus cyst with the scolex attached to the inner wall composes the “hanging drop sign.” This sign was seen in all seven cases studied using simultaneous A-and B-scan sonography. This appearance was consistent and reproducible, regardless of whether the cyst was intraocular or extraocular in location. The “hanging drop sign” may be a useful sonographic parameter in making the diagnosis of an orbital cysticercus cyst.
