Answer to Case 792

Answer to the Parasite Case of the Week 792: Echinococcal cyst, most likely due to E. granulosus.

This case shows several classic findings:

1. A complex cyst on CT with multiple, variably-sized cysts within a larger cyst (i.e., daughter cysts). 
2. A single cyst on initial gross exam that contains fluids and possibly daughter cysts within.
3. A single Echinococcus sp. protoscolex, allowing us to make a definitive diagnosis of echinococcosis. I've enhanced the contrast of the image below to highlight the invaginated scolex with crown of hooklets.

Thanks again to Drs. Ashley Zeoli, Nico Herrera, Luke Pryke, and Paul Blair for donating this great case!