膀胱類澱粉沉積症：病例報告與文獻回顧

游斯鴻、李建儀、王賢祥、楊晨洸、陳正哲

台中榮民總醫院 泌尿醫學部

Amyloidosis of the Urinary Bladder: A Case Report and Literature Review

Ssu-Hung Yu, Jian-Ri Li, Shian-Shiang Wang, Cheng-Kuang Yang, Cheng-Che Chen

Department of Urology, Taichung Veterans General Hospital, Taiwan

Introduction

Amyloidosis of the urinary tract is an uncommon disorder characterized by extracellular deposition of amyloid protein. It may involve the bladder, ureter, or urethra, and often presents with hematuria, mimicking malignancy. Due to its rarity and nonspecific clinical presentation, diagnosis is frequently made only after histopathological evaluation. We present a case of primary bladder amyloidosis initially suspected to be bladder cancer.

Case Presentation

A 68-year-old female with no known systemic disease presented with intermittent painless gross hematuria since 2023. She denied smoking and occupational chemical exposure but reported regular hair dye use every two months. Initial evaluation, including cystoscopy, ultrasonography, and biopsy, revealed an irregular bladder surface on sonography. Intravenous pyelography showed no upper urinary tract abnormalities. Cystoscopy demonstrated tumor-like lesions over the trigone and dome. Under the impression of bladder tumor, TURBt was performed, and all visible lesions were removed. Histopathology confirmed amyloid deposition in the posterior and right lateral bladder walls. The patient was followed up every three months postoperatively, with no recurrence of hematuria and persistently negative urine cytology.

Discussion

Primary bladder amyloidosis is a rare benign condition that can closely mimic bladder malignancy in both clinical presentation and imaging findings. The most common presenting symptom is painless gross hematuria, as seen in this case. Over the past 20 years, only two cases of bladder amyloidosis have been reported in our hospital. Radiologic and cystoscopic findings often show mass-like or irregular lesions, making it difficult to distinguish from urothelial carcinoma preoperatively. Therefore, histopathological examination remains the gold standard for diagnosis. Transurethral resection is both diagnostic and therapeutic. However, recurrence has been reported, and long-term surveillance is recommended. In addition, systemic amyloidosis should be excluded, as bladder involvement may occur in systemic disease.

Conclusion

Bladder amyloidosis should be considered in the differential diagnosis of bladder tumors, especially in patients presenting with painless hematuria and atypical biopsy findings. Histopathological confirmation is essential for diagnosis. TURBt is an effective treatment, but careful long-term follow-up is necessary due to the risk of recurrence.