ENDOMETRIOSIS OF THE UPPER URETER

Endometriosis of the ureter is considered a rare manifestation. There have been >90 cases reported in the last decade but the location has never been above the pelvic brim. Many theories of the pathogenesis have been advanced to explain the presence of endometrium in the ureter. Stanley and associates have suggested that ureteral and bladder involvement arise from pelvic foci. Implantation owing to passage via lymphatics or blood stream is well documented. Sampson's theory of retrograde menstruation is well known, as well as the possibility of metaplasia of the urothelium.