Intravesical urinary bladder duplication in a dog

A 2-year-old intact male Stafforshire bull terrier was admitted for chronic dysuria evolving for 3 months. Computed tomography (CT) scan of the abdomen revealed an intraluminal tubular soft tissue attenuating structure coursing inside the right and cranial aspect of the urinary bladder and fused to the bladder wall (Fig 1A, B). A thin tubular extension, similar in appearance to the abdominal and prostatic urethra, originated from this tubular vesical lesion in the area of the urinary bladder neck, connected its lumen with the ventral part of the right prostatic lobe and reached the prostatic urethra at the centre of the prostate gland. The ureters were identified and unremarkable. An urinary bladder duplication and a duplicated urethra were strongly suspected. Removal of the abnormal structure was performed, and the intra-prostatic urethra-like structure was dissected and removed after catheterization (Fig 1C, D). This structure contained urine. Histological examination was consistent with bladder tissue and confirmed the isolated urinary bladder duplication. Complete resolution of the clinical signs was observed 2 weeks postoperatively and confirmed at 1- and 6-month follow-ups. Ultrasonography revealed complete bladder healing. Urinary bladder duplication is a rare congenital anomaly. It is considered complete when the two bladders are fully separated by a normal bladder wall and are each drained by a separate urethra. In the present case, the duplicated bladder was located inside the main bladder, alongside its wall, and then joined the normal prostatic urethra through an accessory urethra, which was not previously described.