Rheumatoid arthritis-induced pseudotumoral AA amyloidosis of the bladder with vesico-peritoneal fistula

Rheumatoid arthritis-induced AA amyloidosis of the bladder is rare, with fewer than 25 cases reported so far. This localization may be life-threatening with a mortality rate of about 60%, most often due to massive hematuria or multiorgan failure as a result of systemic amyloidosis. We report the case of a 72-year-old woman with a long history of rheumatoid arthritis who developed gross hematuria that induced severe anemia. Ultrasonography and tomodensitometry revealed a large mass localized in the upper part of the bladder. Cystoscopy showed a congestive inflammatory area with a large vesicoperitoneal fistula. Biopsies revealed amyloidosis, and immunohistochemical staining of the specimens defined the process as AA amyloidosis. The amyloid deposits were also found in the rectum, duodenum, uterus and kidneys. This case of rheumatoid arthritis-induced AA amyloidosis of the bladder is characterized by its pseudotumoral aspect and the existence of a vesico-peritoneal fistula: only 2 cases have been reported so far. Treatment was symptomatic, and the patient died from cachexia. The pseudotumoral forms of AA amyloidosis, including amyloidosis of the bladder, deserve an early correct diagnosis. Otherwise, an incorrect diagnosis, especially cancer, may prompt inappropriate treatments.