A case of localized amyloidosis of the bladder manifesting post-renal failure

We report a case of primary localized amyloidosis of the bladder which manifested post-renal failure. A 79-year-old woman with diabetes mellitus complained of anorexia and oliguria. Computed tomographic (CT) scan showed bilateral hydronephrosis. Cystoscopic examination revealed a broad-based nonpapillary tumor in the trigonum of the bladder and CT scan demonstrated thickening of the posterior wall of the bladder. Pathological examination of the transurethral biopsy specimen revealed amyloid deposits in the submucosa, but no malignant changes were found. Cytodiagnosis of washing fluid of the bladder revealed amyloid deposits around the exfoliative cells. Serum electrophoresis showed a normal pattern. Urinary Bence-Jones protein was not detected. Amyloid deposits were not found in rectal mucosa. Systemic or secondary amyloidosis was ruled out from these findings, and primary localized amyloidosis of the bladder was diagnosed. The mass of the bladder was transurethrally resected and pig-tail stents were indwelt. These procedures gave a satisfactory result.