Ureterocele, one of the less common abnormalities of the genitourinary tract, is the intravesical bulging of the mucosa of the lower end of the ureter. Kaufmann stated:1 "If a ureter ends blindly at its vesical end,... or if the vesical end of one or both ureters narrows down to an exceedingly fine opening, the end of the ureter covered with vesical mucosa bulges into the bladder like a bubble or cyst, ureterocele vesicalis." Ureteroceles appear as rounded protrusions at one or both ureteral orifices, and, before the days of cystoscopy, they were discovered only post mortem or accidentally in the course of intravesical operations. DISCUSSIONS IN THE LITERATURE Historical Observations. —Most of the early observations were made at necropsy, the earliest, according to Patch,2 by Lechler,3 in 1835. Civiale4 mentioned cystic dilatation of the ureter in 1843. Lilienfeld5 described the first pathologic specimen of the