Primary bladder amyloidosis.

Primary bladder amyloidosis is a rare disease, with only 200 cases reported worldwide. This condition is clinically important since it masquerades as a malignancy. We herein present a case of primary bladder amyloidosis presenting as painless hematuria and dysuria. Computed tomography and ultrasound showed thickening of the posterior bladder wall. Cystoscopy revealed abnormal bladder tissue suspicious of malignancy. However, transurethral resection of a bladder tumor showed no evidence of malignant cells. Amyloid was identified on Congo red staining. Therefore, the possibility of secondary amyloidosis was ruled out and a diagnosis of primary bladder amyloidosis was made. Nine months after undergoing primary resection, the patient's amyloidosis recurred at the initial site.