Idiopathic retroperitoneal fibrosis: clinicopathologic features and differential diagnosis.
Idiopathic retroperitoneal fibrosis (IRF) is a rare disease often causing obstructive uropathy. We evaluated the clinicopathologic features of 24 patients with IRF to characterize the histopathology of the disease and to provide a framework for the differential diagnosis with other retroperitoneal fibrosing conditions. Retroperitoneal specimens were analyzed by light and electron microscopy and by immunohistochemistry. Most patients presented with abdominal/lumbar pain, constitutional symptoms, and high acute-phase reactants. Overall, 20 had ureteral involvement and 13 developed acute renal failure. The retroperitoneal tissue consisted of a fibrous component and a chronic inflammatory infiltrate with the former characterized by myofibroblasts within a type-I collagen matrix. The infiltrate displayed perivascular and diffuse patterns containing lymphocytes, macrophages, plasma cells, and eosinophils. The perivascular aggregates had a central core of CD20(+) cells and a mantle of CD3(+) cells in equal proportions. In the areas of diffuse infiltrate, CD3(+) cells outnumbered the CD20(+) cells. Most plasma cells were positive for the IgG4 isotype. Small vessel vasculitis was found in the specimens of 11 patients. Our study indicates that a sclerotic background with myofibroblasts associated with a diffuse and perivascular infiltrate mainly consisting of T and B lymphocytes may be a pathological hallmark of IRF.
Corradi
D
D
Department of Pathology and Laboratory Medicine, Pathology Section, University of Parma, Parma, Italy. domenico.corradi@unipr.it
Maestri
R
R
Palmisano
A
A
Bosio
S
S
Greco
P
P
Manenti
L
L
Ferretti
S
S
Cobelli
R
R
Moroni
G
G
Dei Tos
A P
AP
Buzio
C
C
Vaglio
A
A
D058186:Acute Kidney Injury / Q000000981:diagnostic imaging* / Q000209:etiology / Q000473:pathology*; D000328:Adult; D000368:Aged; D001402:B-Lymphocytes / Q000473:pathology; D003937:Diagnosis, Differential; D004804:Eosinophils / Q000473:pathology; D005260:Female; D005347:Fibroblasts / Q000473:pathology / Q000648:ultrastructure; D005355:Fibrosis; D006801:Humans; D007150:Immunohistochemistry; D008264:Macrophages / Q000473:pathology; D008297:Male; D008854:Microscopy, Electron; D008875:Middle Aged; D010950:Plasma Cells / Q000473:pathology; D012185:Retroperitoneal Fibrosis / Q000150:complications / Q000000981:diagnostic imaging* / Q000473:pathology*; D016176:T-Lymphocyte Subsets / Q000473:pathology; D014057:Tomography, X-Ray Computed; D014513:Ureter / Q000000981:diagnostic imaging / Q000276:immunology / Q000473:pathology; D014552:Urinary Tract Infections / Q000150:complications / Q000000981:diagnostic imaging / Q000473:pathology