Liver and intrahepatic bile ducts - Tumor
Dysplasia
Low grade dysplastic nodule

Author: Naziheh Assarzadegan, M.D. (see Authors page)

Editor: Raul S. Gonzalez, M.D.

Revised: 6 February 2017, last major update November 2016

Copyright: (c) 2004-2017, PathologyOutlines.com, Inc.

PubMed search: "dysplastic nodule" liver WITH "low grade"

Cite this page: Low grade dysplastic nodule. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/livertumorlowgradedysplasticnod.html. Accessed June 28th, 2017.
Definition / general
  • Discrete nodules in cirrhotic livers, containing mild architectural changes
Essential features
  • Dysplastic nodules (both low grade and high grade) are associated with higher risk of development of hepatocellular carcinoma
  • Low grade dysplastic nodules have a significantly lower risk to transform into carcinoma than high grade nodules (J Hepatol 2003;39:208)
Terminology
  • Also called macroregenerative nodule type I, adenomatous hyperplasia, hepatocellular pseudotumor
Clinical features
  • Usually ages 40 and older; 2/3 arise in males
  • May progress to hepatocellular carcinoma, but usually stabilize or disappear over time instead
Radiology description
  • Usually isovascular or hypovascular compared to surrounding parenchyma, whereas hepatocellular carcinoma appears hypervascular
Treatment
  • Follow by imaging
Gross description
  • Often distinct nodules (can be vague), separated from the surrounding liver by a rim of thin fibrous scar (not a true capsule)
  • Usually multiple, 0.5 to 1.5 cm, occasionally up to 5 cm
  • Similar in color and texture to surrounding liver, may be pale or bile stained
  • Usually found in cirrhotic livers, rarely in acute liver injury or precirrhotic livers
Microscopic (histologic) description
  • Monotonous cell population lacking architectural atypia, with mild increase in cellularity compared to surrounding cirrhotic liver (Hepatology 2009;49:658, Dig Liver Dis 2011;43 Suppl 4:S361)
  • Portal tracts can be identified within the nodules
  • Liver cell plates 1 - 2 cells thick (highlighted on reticulin stain)
  • Features of hepatocellular carcinoma (pseudoglands or markedly thickened trabeculae) absent
  • May have large cell changes in hepatocytes
  • Unpaired arteries, which have no accompanying bile ducts, can be prominent in number and size (unlike cirrhotic nodules)
  • May have diffuse iron or copper retention (Arch Pathol Lab Med 2011;135:704)
Microscopic (histologic) images
Images hosted on PathOut server:

Courtesy of Naziheh Assarzadegan, M.D.

Mild increase in
cellularity compared
to surrounding
cirrhotic liver



Images hosted on other servers:

Low grade dysplastic nodules

Molecular / cytogenetics description
  • May be clonal
  • Inactivation of p21 checkpoint, in contrast to cirrhotic nodules, which show activation
Differential diagnosis
  • Macroregenerative nodule: similar malignant potential; distinction by morphology alone can be difficult; distinguishing molecular findings include overexpression of semaphorin E, IGF-BP3 and caveolin 1 and increased expression of collagen IV (Lab Invest 2002;82:547, Am J Pathol 2003;162:991)
  • High grade dysplastic nodule: increased hepatocyte density, with moderate cytologic or architectural atypia