Duplication of the renal pelvis and blind-ending bifid ureter in twins.

Blind-ending bifid ureter in a woman with urinary tract infection and a duplicated renal pelvis in her twin sister are reported. The blind-ending bifid ureter terminated as a fibrous cord with a terminal mass of immature renal tissue. This type of ureter may be a transitional form between histologically blind-ending bifid ureter and duplication of the renal pelvis and/or kidneys. Findings in twins support this opinion.