- Clinical science
Retroperitoneal fibrosis (RPF, Ormond's disease) is a rare disease of unknown etiology, characterized by inflammation and fibrosis of the retroperitoneum resulting in compression and encasement of the ureter, and/or the retroperitoneal blood vessels. RPF may be primary/idiopathic (most common) or secondary (e.g., drug-induced, inflammatory, iatrogenic). Patients often present with non-specific symptoms (e.g., fever, malaise, weight loss, flank pain, etc.). Bilateral ureteral obstruction, with subsequent hydronephrosis and obstructive nephropathy, is common. Diagnosis is often suspected in patients who present with bilateral hydronephrosis of unknown etiology. Contrast CT is the diagnostic test of choice and reveals a retroperitoneal mass encasing and obstructing the ureters and/or the aorta and IVC. Diagnosis is confirmed on CT-guided biopsy of the mass. High-dose glucocorticoids are the mainstay of treatment of primary RPF. Secondary RPF is managed by treating the underlying cause (stopping the offending drug, treating the infection, etc.). Symptomatic/severe obstruction of the retroperitoneal structures require treatment (ureteric stenting, ureterolysis, arterial stenting, etc.). Prognosis of non-malignancy-induced RPF is good, but recurrence rates are high (70%).
Primary/idiopathic retroperitoneal fibrosis
- Immune reaction to antigens within aortic atherosclerotic plaques
- Systemic autoimmune disease: RPF may be a systemic autoimmune disease of large arteries → periaortic inflammation → inflammation and fibrosis in the periaortic region
- IgG4-related disease (immunoglobulin G4 related disease): characterized by an infiltration of various organs by IgG4-bearing plasma cells which cause inflammation and fibrosis
Secondary retroperitoneal fibrosis
- Drugs: ergot alkaloids (methysergide; , ergotamine) ; Dopamine agonists (pergolide, methyldopa), β-blockers, analgesics (phenacetin), hydralazine, etc.
- Biological agents: infliximab, etanercept, etc.
- Malignancies: primary retroperitoneal malignancies , Retroperitoneal metastases , carcinoid tumors
- Infections: mycobacterium tuberculosis, actinomycosis, histoplasmosis
- Iatrogenic: surgery or radiation therapy to the retroperitoneum
- Trauma: retroperitoneal hemorrhage
- Tobacco use
- Exposure to asbestos
Malignancies and exposure to methysergide are the most common causes of secondary RPF!
- Pain in the lower back/flanks; (most common symptom)
- Constitutional symptoms: fever, anorexia, weight loss, nausea, etc.
- Specific symptoms
- Ureters → → and features of (: uremia, hypertension, etc.)
- Infrarenal aorta/iliac arteries → chronic mesenteric ischemia, lower limb and gluteal claudication pain, etc.
- Inferior vena cava/iliac veins →deep vein thrombosis, renal vein thrombosis
- Gonadal vessels → pain , , testicular
- Lymphatic channels → lymphedema
- Laboratory tests
Contrast-enhanced CT scan
- Investigation of choice to diagnose RPF
- CT-guided biopsy of the mass
- MRI and MRA: useful in patients in whom contrast administration is contraindicated
- Intravenous urography and retrograde pyelography 
- Renal ultrasonography: useful in assessing response to therapy
- Contrast-enhanced CT scan
- Biopsy (confirmatory test)
- Primary RPF
- Secondary RPF
Decompression of obstructed retroperitoneal structures
Kidneys and ureters: (see treatment of )
- Conservative therapy:
- Surgical decompression: open/laparoscopic ureterolysis (release of the ureter from fibrotic tissue) 
- Aorta or iliac arteries: see “Revascularization” in
- IVC or iliac veins: see “Treatment” in