[Pyonephrosis Caused by Ureteral Stricture Due to Syphilitic Granuloma: A Case Report].

An 87-year-old woman was admitted to our hospital with anorexia, lightheadedness, and fever. She was referred to our department with a diagnosis of right pyonephrosis due to stenosis of the right ureter. The severe stenosis made it impossible to place a ureteral stent. Nephrostomy was performed and the infection improved. Antegrade pyelography and contrast CT did not reveal the cause of the stenosis. Considering the reduced quality of life due to the nephrostomy and the possibility of ureteral stricture due to malignancy, the patient underwent right nephrectomy at a later date. Pathological examination revealed an abscess and granuloma around the ureteral stenosis. Immunostaining showed a large number of fungi positive for Treponema pallidum within the granuloma. Therefore, the patient was diagnosed with ureteral stricture due to syphilis.