Retroperitoneal fibrosis

Rare entity with increased retroperitoneal tissue with chronic inflammation and fibrosis which can entrap the ureter or other organs.

Idiopathic in two-thirds of cases, with the remainder cases secondary to neoplasms, trauma, infectious processes, radiation, surgery and certain drugs.

In a Finnish study incidence of idiopathic disease 0.1 per 100,000 person-years and a prevalence of 1.38 per 100,000 population.

Estimated annual incidence varies from 1 per 200,000-500,000 population.

Because of the its nonspecific symptoms, the diagnosis is often delayed and may lead to progressive loss of renal function.

Childhood presentation is extremely rare.

Mean onset 50-60 years of age with men affected 2-3 times as often as women.

Can occur in children and in the elderly.

Characterized by the development of extensive fibrosis throughout the retroperitoneum, usually centered over the anterior surface of the fourth and fifth lumbar vertebrae.

Can lead to entrapment and obstruction of retroperitoneal structures, especially the ureters.

Involvement of the inferior vena cava and lymphatics may result in compression or thrombosis and leads to lower-limb edema.

Gonadal vessel may cause scrotal edema, rarely, the duodenum, biliary tract, pancreas, large bowel, and mesentery are involved.

Malignant retroperitoneal fibrosis is associated with poor prognosis, with average survival of approximately 3-6 months.

Idiopathic retroperitoneal fibrosis carries a good prognosis.

Sixty to 70% of cases of retroperitoneal fibrosis are idiopathic..

Etiologic factors include chronic peritoneal irritation, and irradiation.

In approximately 8% of patients. is associated with malignancy to carcinomas of the breast, lung, stomach, colon, bladder, prostate, and cervix.

Metastatic tumor cells in the retroperitoneum cause a desmoplastic reaction,

Malignantly induced retroperitoneal fibrosis displaces the ureter medically on radio graphic examinations.

Immune-mediated connective-tissue diseases associated with RF include: Ankylosing spondylitis, systemic lupus erythematosus, scleroderma, systemic vasculitis, Wegener’s granulomatosis, polyarthritis,, Reynards disease, rheumatoid arthritis, and immune complex membranous ground glomerulonephritis.

Can be associated with Crohn disease, ulcerative colitis, and sclerosing cholangitis.

Responds to corticosteroids and immunosuppressive therapy suggesting it is immunologically mediated.

Approximately 8% of cases are associated with metastatic malignancy.

The symptoms and signs are nonspecific.

Definitive diagnosis made by biopsy.

Duration of symptoms prior to diagnosis is approximately 6-12 months.

Greater than 90% of patients present with dull, poorly localized, noncolicky pain in the flank, back, scrotum, or lower abdomen.

Less common symptoms include fever, lower-extremity edema, phlebitis, and deep venous thrombosis.

Children , may have hip or gluteal pain.

Uncommonly patients present with weight loss, nausea, vomiting, anorexia, and fatigue.

Rare manifestations include: Raynaud phenomenon, ureteric colic, and hematuria.

Physical findings due to late complications include : peripheral edema, ascites, thrombosis, bowel obstruction.

Intravenous urography may provide support for the diagnosis.

CT scanning or MRI is essential for evaluating the extent of the disease.

Pathogenesis not been definitively described.

Suggested that the process is an immunologic response to antigens within atherosclerotic plaques, as fibrosis often begins around a severely atherosclerotic aorta, as demonstrated on autopsy and radiographic studies.

Plaque formation may allow insoluble lipids, such as ceroid, an oxidized low-density lipoprotein, to leak into periaortic tissue.

Ceroid containing macrophages in lymph nodes in approximation of the fibrosis and vascular plaques has been noted.

Frequently associated with aortic aneurysms.

Retroperitoneal fibrosis regression has been reported following aneurysm repair.

Explanation for the presence of RF in children, or in those without aortic aneurysm is not presently available.

Drugs such as beta-blockers, methysergide, and methyldopa have been implicated as etiologic agents, with secondary hypersensitivy or autoimmune reactions.

Fibrosis reaction associated with carcinoid tumormay be due to circulating serotonin or its metabolites.

Occasionally associated with connective tissue disorders, familial disorders, and HLA-B27 gene.

Associated with the Hyper IgG4 syndrome.

Associated with asbestosis exposure.

Higher risk in smokers.

Lab findings include elevated ESR, increased IgG4, presence of autoantibodies, HLA-B27, elevated urea and creatinine levels, normocytic normochromic anemia, elevated C-reactive protein level, polyclonal hypergammaglobulinemia, elevated alkaline phosphatase, and antinuclear antibodies in 60% of cases.

Urinalysis is usually normal, but rarely microscopic hematuria or pyuria is present.

Ureteral obstruction often appears minimal in the presence of severe renal failure, suggesting impaired peristalsis is a significant contributor to the process.

The aims in management is to preserve renal function, reduce morbidity, and suppressing inflammation.

Ureterolysis is the pref2242ed treatment as it it allows biopsy specimens to be obtained and relieving ureteral obstruction.

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