Ureteral endometriosis: a rare and underdiagnosed cause of kidney dysfunction.

Little attention has been paid by the renal literature to ureteral endometriosis, a rare and silent disorder that can eventually lead to renal failure. In endometriosis, the ureteral involvement can be limited to a single ureter, more often the left one, or both ureters with consequent urine tract obstruction and ureterohydronephrosis. In most cases, the ureteral obstruction is caused by endometrial tissue surrounding the ureter (extrinsic ureteral endometriosis). In the remaining cases, endometrial cells are located within the ureter (intrinsic ureteral endometriosis). Progressive ureteral obstruction can be insidious in onset and can ultimately lead to renal failure if a correct diagnosis is missed. The true incidence of renal failure caused by endometriosis is completely unknown, although cases have been reported in the literature. The diagnosis of ureteral endometriosis is difficult since the disease may be clinically silent or associated with non-specific symptoms. Only a high index of suspicion and radiological support may help to obtain an early diagnosis. However, while renal imaging is useful in the cases of extrinsic endometriosis, the diagnosis of intrinsic endometriosis often requires ureteroscopy or laparoscopy. The prognosis of ureteral endometriosis depends on the time of diagnosis. In too many cases of bilateral obstruction, the patient is referred to the nephrologist because of an advanced, irreversible renal failure. Although some patients may benefit from progestin or anti-arotamase therapy, in most cases of ureteral endometriosis surgery is needed, laparoscopy surgery being preferred today to laparatomy.