Localized amyloidosis of the urinary tract: case series of nine patients.

OBJECTIVES

To report 9 cases of primary localized amyloidosis of the urinary tract and correlate the pathologic findings with clinical and cystoscopic information.

METHODS

Patients diagnosed with amyloidosis of the ureters, urinary bladder, or urethra from 1976 to 2003 were identified. Their medical records were reviewed, and histochemical and immunoperoxidase stains were performed on the tissue.

RESULTS

Eight cases of amyloidosis of the urinary bladder and one of the renal pelvis/ureter were identified. None of our cases showed evidence of systemic amyloidosis. Of the 8 patients with amyloidosis of the urinary bladder, 5 presented with gross hematuria and 1 with irritative bladder symptoms and 2 had amyloidosis detected during cystoscopic follow-up for urothelial carcinoma. The patient with amyloidosis of the renal pelvis/ureter presented with flank pain and gross hematuria. The clinical impression was malignancy in 75% of the bladder cases. Most patients with bladder involvement were treated with localized bladder resection; however, 1 patient required total cystectomy for symptom control. Of 5 patients with follow-up information, 2 developed recurrence. The pathologic assessment diagnosed amyloid deposits consistent with primary or AL type amyloid in all cases. Immunoperoxidase stains revealed lymphoid cells in the vicinity of the amyloid deposits to be lambda-restricted in 78% of cases.

CONCLUSIONS

Primary amyloidosis of the urinary tract is a rare condition that mimics malignancy in its clinical presentation and cystoscopic appearance and on diagnostic imaging. In our study, all cases of urinary amyloid deposits represented localized amyloidosis rather than manifestations of systemic amyloidosis. Monoclonal lymphoid populations evolving from chronic inflammation in the urinary tract may be the source of the amyloid AL proteins.