Background: a 17 years-old girl with a Mitrofanoff appendicovesicostomy developed a large bladder clot due to hematuria after a surgical cystolithotomy in an augmented bladder. Trans-urethral approaches were not feasible due to a previous surgical closure of the bladder neck. Methods: after an unsuccessful trans-appendicovesicostomy bladder washing, the endoscopic evaluation was performed using a 14 Ch rigid cystoscope, surrounded by its own urethral sheath. The clot was progressively fragmented through the cystoscope and a urethral catheter under direct vision. Clot fragments were aspirated obtaining a complete evacuation; Results: the urethral sheath prevented damages to the appendicovesicostomy, allowing at the same time repeated accesses of the cystoscope into the neobladder and ensuring the success of the procedure; Conclusions: the use of urethral sheath 14 Ch though an appendicovesicostomy preserves both the stoma and the channel, making possible endoscopic procedures as blood clot evacuation into the neobladder.