Introduction. Ureteroscopy is the primary treatment modality for patients with ureteral stones. Despite its high efficacy, this intervention can be associated with severe complications, among which ureteral avulsion is considered one of the most serious. An even rarer complication is mucosal avulsion, with only isolated cases reported in the literature.

Clinacal case. We present the case of a patient with a stone in the upper third of the right ureter who underwent prestenting due to a narrowing of the distal ureter. Three weeks later, during the planning of lithotripsy, the ureteral stent was removed, along with a tubular tissue fragment prolapsing from the ureteral orifice, which clinically and macroscopically resembled a segment of the ureter. Intraoperative ureteroscopy revealed preservation of the ureteral wall integrity with a circumferential defect of the mucosa. A ureteral stent was placed. Histopathological examination of the excised fragment revealed mucosal tissue with marked eosinophilic infiltration. At four-week follow-up, a repeat endoscopic procedure demonstrated complete restoration of the mucosa. Subsequent imaging confirmed the absence of residual fragments and maintained ureteral patency.

Conclusions. Ureteral mucosal avulsion is a rare complication of ureteroscopy. Conservative management with ureteral stenting and close follow-up is often sufficient, helping to avoid unnecessary surgical procedures. Further reporting of such cases will aid in developing evidence-based diagnostic and treatment algorithms.