Malacoplakia of the urinary tract affects primarily the bladder and secondarily the distal ureter. Characteristic gross and microscopic lesions have been well described. A case of malacoplakia is reported in a 55-year-old woman who presented with hydronephrosis in a solitary kidney. The only lesion in the urinary tract was an apple-core type mass of the distal ureter, which was resected. This represents a rare and unusual presentation of malacoplakia. The differential diagnosis and pertinent literature are discussed.