Case 29 Answer

Check out the dome of the bladder and how it is pulled anterior and upward, with a thin strand of tissue (which had a small amount of fluid) extended up towards the umbilicus.

Answer: Vesicourachal diverticulum

Part of a spectrum of urachal remnants, the urachus should become obliterated post birth and turn into the median umbilical ligament. Persistence of parts or all or the urachus lead to everything from a patent urachus (technically would act as a fistula between the bladder and the umbilicus) to a urachal cyst (a cyst not connected to the umbilicus or bladder) or a umbilical or vesicular diverticulum). This was in an asymptomatic person and the cranial part was essentially non-existent so I called it a vesicourachal diverticulum.

http://radiopaedia.org/articles/congenital-urachal-remnant-abnormalities

http://www.ajronline.org/doi/pdf/10.2214/ajr.137.5.1063