When symptoms are apparent, they often present as occasional or continuous incontinence, and inflammation of the vagina (vaginitis) from urine scalding the vaginal tissue. Holt P E & Gibbs C (1992) Congenital urinary incontinence in cats: a review of 19 cases. As many dogs with ectopic ureters can have other concurrent urinary tract abnormalities, incontinence can remain in some cases. Ectopic ureters are an abnormality whereby dogs and cats are born with ureters that do not enter the bladder in the correct position resulting in incontinence. In one study around 50% of cases were continent with this procedure alone and the others required additional treatment (most commonly medical treatment of urethral sphincter mechanism incompetence). In some dogs and cats the ureters enter in the wrong place, hence the term "ectopic." This abnormality is something that cats and dogs are born with and can affect one or both of the ureters. Cats have two ureters, from the left and right kidneys. Instead, they bypass the bladder and go into the urethra, or in females, the vagina or the uterus.
An ectopic ureter refers to a developmental problem where one or both ureters implant in the wrong location. With ectopic ureters, one or both of the ureters do not connect normally to the bladder.

Burbridge H M, Jones B R & Mora M T (1989) Ectopic ureter in a male cat. In cats, the most common location for ectopic ureters to be located is the urethra (the tube through which the bladder voids urine). This means that the urine may not go directly into the bladder and may enter into the urethra (the tube from the bladder to the outside world) or into another part of the urinary or reproductive system. Since these organs are not equipped for urine storage, like the bladder… Vet Rec 130 (20), 437-442 PubMed. Steffey M A & Brockman D J (2004) Congenital ectopic ureters in a continent male dog and cat. An ectopic ureter is an abnormality of the ureter (the tubular tissue that connects the kidney to the urinary bladder) where the ureter does not enter into the urinary bladder in the correct anatomic position. Most ectopic ureters (>95%) are classified as intramural which mean they tunnel inside the bladder wall and are amenable to … This condition is rare, and when it does occur it may be asymptomatic, with no apparent urination problems. J Am Vet Med Assoc 224 (10), 1607-1610 PubMed.