Case 17 Answer

OK, this was a tough one. I don’t know if the movie helped or hindered but hopefully you see the 2-3cm cystic mass in the RLQ. The first few images were meant to show a connection to the bowel, ie the cecum. So with this information, a spherical cystic mass extended from the base of the cecum, the diagnosis is:   appendiceal mucocoele  but unfortunately I don’t think there is a good way to exclude malignancy (mucinous cystadenoma/cystadencarcinoma) - see reference 2 below.

reference: http://radiopaedia.org/articles/appendiceal-mucocoele

or more detail: http://www.ajronline.org/doi/full/10.2214/AJR.12.9260