[Primary AA type amyloidosis of the urinary bladder: a case report]

Primary amyloidosis of the urinary bladder is a rare disease entity. A total of 61 cases have been reported in the Japanese literature, and most of them were AL type amyloidosis. We report here a case of primary AA type amyloidosis. A 52-year-old man presented with a chief complaint of asymptomatic gross hematuria. Cystoscopy revealed yellowish elevated lesions, transurethral mucosal biopsies were performed, and the histopathological diagnosis indicated a primary AA type amyloidosis of the urinary bladder. Systemic amyloidosis was clinically eliminated. The yellowish lesions in the bladder through cystoscopy disappeared spontaneously one year later without any specific treatment, but periodical work-up may be necessary to rule out recurrence of the disease or bladder tumor.