Primary Localized Amyloidosis of the Urinary Bladder Mimicking Urothelial Carcinoma: A Case Report.

Primary localized amyloidosis of the urinary bladder is a rare benign condition that can closely mimic urothelial carcinoma clinically and cystoscopically, particularly in patients presenting with visible hematuria. We report the case of a 79-year-old gentleman with persistent visible hematuria who underwent flexible cystoscopy, computed tomography urography, transurethral resection of bladder tumor, histopathological assessment, thoracic imaging, and hematological evaluation, including serum free light chain analysis. Cystoscopy revealed a suspicious bladder lesion concerning for malignancy, but histopathology demonstrated localized amyloid deposition within the bladder wall without evidence of urothelial carcinoma. Subsequent imaging and hematological work-up showed no evidence of systemic amyloidosis, and multidisciplinary review supported a diagnosis of primary localized bladder amyloidosis. The patient recovered without perioperative complications and was advised long-term cystoscopic surveillance because of the risk of recurrence. This case highlights localized bladder amyloidosis as an important differential diagnosis for persistent visible hematuria and suspicious bladder lesions, emphasizing the need for histopathological confirmation and exclusion of systemic disease to avoid unnecessary radical intervention while ensuring appropriate follow-up.