Unveiling an Inverted Papilloma of the Bladder: A Case Series and Literature Review

Bladder inverted papilloma (BIP) is a rare, benign urothelial lesion that can mimic urothelial carcinoma endoscopically but is characterized histologically by an endophytic growth of anastomosing urothelial cords without muscular invasion. We report a single-center case series of four patients managed with complete transurethral resection between January 2022 and August 2025, with the inclusion criterion being a histopathological diagnosis: a 28-year-old man with a trigonal lesion complicated by bladder perforation that healed uneventfully, a 72-year-old man in whom a small peri-orificial lesion was resected during urgent ureteric stenting and subsequently followed on a low-risk bladder cancer pathway with no recurrence at three years, an 84-year-old man with a large polypoid lesion arising near the bladder neck that was completely excised, and a 72-year-old woman with a pedunculated lateral wall mass treated by resection and single-dose intravesical mitomycin, remaining disease-free at one year. Synthesizing contemporary evidence and our experience, we highlight that accurate histopathological confirmation, complete endoscopic excision, and multidisciplinary discussion are key to management; routine intensive cystoscopic surveillance appears unnecessary for unequivocal bladder BIP, whereas selective follow-up is reasonable when pathology raises a differential of low-grade urothelial neoplasm with inverted growth or when lesions arise outside the bladder, where malignant association is higher. These findings support a pragmatic, risk-adapted follow-up strategy after complete resection.