[Nephrogenic adenoma of the ureter: a case report].

A 27-year-old male with nephrogenic adenoma of the ureter complicating urolithiasis is reported. Nephrogenic adenoma of the ureter is extremely rare, and this case is the sixth reported in Japan. The lesion was found at the site of the stone in the left ureter. Histopathologically, the tumor consisted of ducts resembling uriniferous tubules, and no signs of malignancy were noted. The cause of nephrogenic adenoma is considered to be metaplastic reaction to stimulation by stones and inflammation.