Primary localized amyloidosis of the urinary bladder. A case report

We present case 96 (the first one in Bulgaria) of primary localized amyloidosis of the urinary bladder in a 72-year-old woman with episodes of painless hematuria. The amyloid tumor is situated on the anterior wall of the bladder--a yellowish prominence 15 mm in diameter with superficial erosion that is surrounded by a reddish ring and bullous edema of the mucosa. Rough and regularly pink perivascular deposits, thickened vessel walls and focal lymphoplasmocyte infiltrates are present in the submucosa. After preliminary treatment with KHMnO4, AL-amyloid is detected in polarized light by Congorot staining and in ultraviolet light using thioflavin. Immunoglobulins and C3 deposits are not found. On electron microscopy deposits of amyloid fibrils are seen in abundance close to collagen bundles. Diseases that may be associated with systemic amyloidosis have been clinically excluded. Nodular amyloidosis resulting from a local immune dyscrasia is accepted in the case. The patient is in good health 11 months after the first biopsy. A literature review on this rare form of localized amyloidosis has been made. Generally, the disease has a favorable prognosis and non-active behavior is recommended. Intravesical instillations of dimethyl sulfoxide, sectional resection or plastic surgery that preserve the urinary tract are used in the rare case of progressive course.