A case of localized amyloidosis of the right ureter treated effectively by occulusive dressing technique therapy using dimethyl sulfoxide: Long-term follow-up of eight years

The patient was a 56-year-old female. She was referred to our department for further examination of right hydronephrosis in 2010. Computed tomography (CT) showed right hydronephrosis, and retrograde pyelography (RP) revealed stenosis of the right lower ureter. Urine cytology was negative. Transurethral biopsy of the right ureter was performed using ureteroscopic cup forceps and the histopathlogical diagnosis was ureteral amyloidosis. A whole-body search was performed, including rectal biopsy, but no evidence of amyloidosis was obtained. She was diagnosed with localized amyloidosis of the right ureter. A ureteral stent was indwelled and the patient was given occulusive dressing technique (ODT) therapy using dimethyl sulfoxide (DMSO) for 1 year. After ODT therapy, right hydronephrosis improved. After a 2-year followup, it worsened. ODT therapy was restarted and continued for 2 years. She consulted our department because of fever and right lumbago in April 2017 after a 4-month interruption of ODT therapy. CT revealed progression of the right hydronephrosis. A ureteral stent was indwelled. and ODT therapy was restarted. The right hydronephrosis improved after 1 year. ODT therapy using DMSO was effective for localized ureteral amyloidosis, but periodic follow-up was necessary and ODT therapy was also effective when it recurred after the interruption of treatment.