Case 51: Echinococcosis, cystic (hydatid)
15 year old girl with fullness in the right upper quadrant.
CT: WHO type CE3, "snake sign", large
Large single cyst (WHO type CE3): delaminated membranes of the endocyst are floating within the main cyst ("snake" or "serpent" sign) as a sign of response to treatment. Note subtle pericystic edema and absent enhancement of the membrane, since this is part of the parasite. Enhancing septations are typically seen in biliary cystadenomas.
Courtesy Dr. Ayse Secil Eksioglu, Dr. Sami Ulus Women and Children's Hospital, Department of Radiology, Ankara, Turkey.