Nodular
Regenerative Hyperplasia (NRH)
Epidemiology:
- associated
with conditions causing heterogenous intrahepatic circulation,
particularly in portal veins and arteries:
- mild outflow
obstruction (not major outflow obstruction – cirrhosis)
- portal tract
inflammatory diseases
- PBC especially
- vasculitides
- Polyarteritis
nodosa (PAN)
- systemic
sclerosis
- SLE
- rheumatoid
arteritis
- solid organ
transplant (esp. renal)
- bone marrow
transplant
- mass effect
-
Common sites:
Gross features:
- diffuse nodular
parenchyma (by definition)
- 1-2mm nodules
- capsular surface
may have minimal irregularities that may be mistaken for cirrhosis
- prominent nodules
may be mistaken for malignancy clinically (note mass effect of a
malignancy can cause NRH surrounding)
- affects the entire
liver
- roughly spherical
nodules
- absence of fibrosis
Histologic features:
- no prominent
fibrosis (by definition)
- nodules are
separated by atrophic parenchyma rather than fibrosis (DDx cirrhosis)
- plump hepatocytes
- rims of atrophic
cells
- reticulin stain
brings out architectural changes
Immunophenotype:
Marker:
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Sensitivity:
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Specificity:
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Molecular features:
Other features:
- associated with
portal hypertension, without ascities usually
References:
- Robbins 2005
- Surgical Pathology
of the GI Tract, Liver, Biliary Tract, and Pancreas (Odze, 2004)