A clinical entity of multiple ureteral fibroepithelial polyps with annular stenosis and tortuosity: clinical features and management considerations.

Background Ureteral fibroepithelial polyps (FEPs) are rare. The management of multiple polyps presents unique challenges, particularly when combined with other variants. These complex cases warrant individualized surgical planning.

Objective To characterize a distinct subset of complex ureteral FEPs defined by the triad of multiple annular stenosis, tortuous ureter, and multiple polyps-collectively termed "MASTUMP," and to investigate its clinical, pathological, genetic features, and management considerations.

Design Single-center retrospective study.

Methods This study included nine patients treated for complex ureteral polyps between December 2019 and October 2024. Inclusion criteria required the presence of multiple FEPs (⩾3), ureteral tortuosity, and annular stenosis (⩾50% luminal narrowing). Clinical characteristics, imaging findings, surgical details, histopathology, and whole-exome sequencing (WES) were collected. Surgical outcomes and follow-up data were analyzed.

Results The cohort (77.7% male, mean age 35.1 ± 13.1 years) presented with bilateral (55.5%) or left-sided (44.4%) polyps, with a median lesion length of 4 (range 1-6) cm. All patients had a history of failed endoscopic or surgical management. According to the society of fetal urology grading system, hydronephrosis was classified as grade 1 in one case, grade 2 in three cases, grade 3 in four cases, and grade 4 in one case, with a mean anterior posterior diameter of 2.43 ± 0.88 cm. WES identified mutations in NRIP1 and TSC2 in two patients. Surgical management included segmental ureterectomy with reconstruction via ureteroureterostomy (two cases), pelvic flap (one case), lingual mucosal graft (one cases), and ileal ureter replacement (five cases). Over a median follow-up of 46.3 (range 11.5-75.4) months, no recurrences were observed.

Conclusion MASTUMP syndrome represents a clinical entity within complex ureteral polyps, potentially associated with congenital anomalies of the kidney and urinary tract. Endoscopic treatment carries a high risk of recurrence and should be approached with caution. Surgical resection with individualized reconstructive strategies offers durable outcomes. Further genetic studies and multicenter validation are essential to refine diagnostic criteria and treatment strategies.