Retroperitoneal fibrosis is a rare inflammatory disorder in which abnormal formation of fiber-like tissue (fibrosis) occurs behind the membrane that lines the cavity of the abdomen (peritoneum). This abnormal tissue growth often spreads to affect the tubes that carry urine from the kidney to the bladder (ureters). Often these tubes become blocked by the excess tissue. Specific symptoms may vary depending upon the exact location of tissue growth and how far it spreads. In most cases the cause of this disorder is unknown (idiopathic).
The most common symptom of retroperitoneal fibrosis is pain in the lower back or abdomen. In many cases this pain is dull, vague and difficult to localize. Additional symptoms may be weight loss, fever, nausea, a low level of circulating red blood cells (anemia), and loss of appetite. Impaired movement of a limb may occur intermittently and abnormal yellow discoloration (pigmentation) of the skin and the whites of the eyes (jaundice) may be present. Swelling of one leg may also occur. Reduced blood flow to the leg may cause pain and discoloration.
Occasionally there may be bleeding (hemorrhaging) in the stomach and intestine. In about ten percent of the cases there may be difficulty urinating. Upon examination by a physician, a mass can be felt in the rectum or abdomen in about 15 percent of individuals with this disorder. In some cases, obstruction of one or both of the tubes that carries urine from the kidney into the bladder (ureters) may also occur (unilateral or bilateral obstructive uropathy). This results in the blockage of the flow of urine and the abnormal accumulation of urine.
Depending upon where the obstruction occurs, the accumulation of urine may result in the pelvis and kidney duct becoming swollen with urine (hydronephrosis). High blood pressure (hypertension) and, eventually, kidney (renal) failure may also occur. Symptoms of renal failure include nausea and vomiting.
In rare cases, retroperitoneal fibrosis may become malignant. In some affected individuals the largest vein in the body that returns blood to the heart (inferior vena cava) may be encased by the fibrous tissue. This encasement rarely causes obstruction of the vein.
The exact cause of retroperitoneal fibrosis is not known in about two-thirds of the affected individuals (idiopathic). A drug used in the treatment and prevention of migraine headaches (methysergide) may be the cause of this rare disorder in 12 percent of cases. Malignant tumors are associated with retroperitoneal fibrosis in eight percent of affected individuals. Tissue that has been injured by trauma or surgery may be a factor in some cases.
Retroperitoneal fibrosis affects males twice as often as females. The majority of cases occur in individuals between 40 and 60 years of age. However, the disorder can occur at any age, although it is extremely rare in children.
Treatment of retroperitoneal fibrosis depends on the location and extent of the tissue growth.
Surgery is often very successful in freeing an organ that has been constricted by retroperitoneal fibrosis. Surgery may also be used to remove a fibrous mass. Obstruction of the ureter is often treated with ureterolysis, a surgical procedure used to free a ureter from surrounding tissue (e.g., abnormal fibrous tissue). In some cases, stents may be implanted within the ureter to provide temporary relief from obstruction.
Corticosteroid drug therapy may be used in the early stages of the disease, in conjunction with surgery, or in affected individuals who are at high risk if surgery is performed.
In some cases, abnormal fibrous growth may recur months or years after surgery or steroid therapy. In some cases, physicians may wrap a layer of fat around the ureter in an attempt to prevent the recurrence of ureter obstruction. In some reported cases, retroperitoneal fibrosis has subsided on its own without treatment (spontaneous resolution).
Retroperitoneal fibrosis has been treated successfully with the drug azathioprine in a few cases. Another drug, Progesterone, has been used in Latin America for the treatment of retroperitoneal fibrosis. More research is needed to determine the long-term safety and effectiveness of these experimental treatments.
The drug tamoxifen has been used to treat individuals with retroperitoneal fibrosis with positive results. However, more research is necessary to determine the long-term safety and effectiveness of this potential treatment for individuals with retroperitoneal fibrosis.
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