Abstract

Primary localized amyloidosis confined to the urinary tract is uncommon and frequently misinterpreted due to clinical and radiologic overlap with more prevalent conditions. We describe a 69-year-old woman who experienced recurrent gross hematuria over 2 years and underwent initial transurethral resection based on a presumptive diagnosis of chronic cystitis. Subsequent evaluation revealed a left ureteral mass with hydronephrosis, raising concern for malignancy. Histopathologic examination of both bladder and ureteral specimens demonstrated amorphous eosinophilic deposits that stained positive with Congo red and showed apple-green birefringence under polarized microscopy. Immunofluorescence confirmed λ-light-chain predominance, establishing AL (amyloid light chain)-type amyloidosis without systemic involvement. The patient underwent complete endoscopic resection and remains asymptomatic during ongoing surveillance. This case highlights the diagnostic challenges posed by localized urinary amyloidosis and underscores the importance of histologic confirmation in atypical inflammatory lesions.

• Keywords: Amyloidosis, Urinary bladder diseases, Cystitis