Liver & intrahepatic bile ducts

Benign / nonneoplastic

Segmental atrophy


Editorial Board Member: Monika Vyas, M.D.
Deputy Editor-in-Chief: Catherine E. Hagen, M.D.
Elaina Daniels, M.D.
Naziheh Assarzadegan, M.D.

Last author update: 15 March 2022
Last staff update: 15 March 2022

Copyright: 2022, PathologyOutlines.com, Inc.

PubMed Search: Segmental atrophy liver[TI]

Elaina Daniels, M.D.
Naziheh Assarzadegan, M.D.
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Cite this page: Daniels E, Assarzadegan N. Segmental atrophy. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/livertumorsegmentalatrophy.html. Accessed December 10th, 2022.
Definition / general
  • Rare, underrecognized benign entity, which can present as a mass lesion (pseudotumor)
  • Typical features of segmental atrophy include loss of hepatic parenchyma, mild inflammation, abnormal vessels, bile ductular proliferation, biliary retention cysts and early fibrotic and elastotic changes
Essential features
  • Unifocal, benign mass lesion
  • Pathophysiology involves a possible vascular injury and ischemia with subsequent elastin remodeling by liver myofibroblasts
  • Histologically, the lesions display extinction of hepatocytes with elastin deposition, thick walled blood vessels and biliary duct cystic changes
Terminology
  • Nodular elastosis of the liver
  • Hepatic segmental atrophy
  • Hepatic pseudotumor
ICD coding
  • ICD-10:
    • K76.89 - other specified diseases of liver
    • K72.90 - atrophy of liver
  • ICD-11: DB97.Y - other specified inflammatory liver disease
Epidemiology
Sites
  • Liver; usually subcapsular but can involve any part of the liver parenchyma
  • No predilection for specific lobes or segments
Pathophysiology
  • Elastic fibers composed of elastin and microfibrils are present in portal tracts, walls of large vessels and central veins in the normal liver
  • Ischemic injury to the liver results in disorganized, excessive elastin deposition by hepatic myofibroblasts, chronic inflammation and vascular fibrosis
Etiology
Diagrams / tables

Contributed by Naziheh Assarzadegan, M.D.

Segmental atrophy stages

Clinical features
  • Can present with right upper quadrant pain, ascites or a palpable abdominal mass or it may be discovered incidentally in an asymptomatic patient
Diagnosis
  • Imaging, such as ultrasound, CT or MRI
  • Requires tissue confirmation due to similar radiographic appearance to many malignant lesions
Laboratory
  • No specific diagnostic laboratory tests
  • Liver transaminases and bilirubin studies are usually within normal limits
  • Alpha fetoprotein levels are not elevated (as seen with hepatocellular carcinoma)
Radiology description
  • Iso or hypoechoic on ultrasound with ill defined margins and no Doppler flow
    • Can resemble malignant neoplasm
  • Well circumscribed, hypodense, noncontrast enhancing mass on CT
    • May be partially calcified
  • Hypointense on T1 weighted MRI due to edema, arterioportal shunting and fibrosis
  • Iso to hyperintense on T2 weighted MRI and diffusion weighted images (DWI)
    • May be hyperdense if adjacent to fatty changes of the liver
  • Isometabolic to background hepatic parenchyma on PET / CT
    • PET / CT or serial imaging can be used to help differentiate from malignant process
  • Reference: Abdom Radiol (NY) 2017;42:2447
Radiology images

Contributed by Naziheh Assarzadegan, M.D.

Mass,
concerning for
cholangiocarcinoma

Prognostic factors
  • Benign condition with favorable prognosis
Case reports
Treatment
  • Complete excision of the lesion
Gross description
  • Often presents as a unifocal, yellow-white, ill defined or well circumscribed mass that can involve any part of the liver
  • Varies in size (1.8 - 10.0 cm) and is typically subcapsular
  • Cut surface is ill defined and variegated with tan-white coloration and areas of hemorrhage (Dig Dis Sci 2014;59:3122)
  • Can have a nodular appearance in later stages due to dense elastosis and fibrosis
  • May have grossly apparent biliary duct dilation with bile duct cysts, resembling a biliary cystic neoplasm
Microscopic (histologic) description
  • Demonstrates a spectrum of elastotic change (Am J Surg Pathol 2011;35:364):
    • Early stage:
      • Collapsed hepatic parenchyma with islands of residual hepatocytes
      • Chronic inflammation
      • Prominent bile duct proliferation
      • Mild elastosis
    • Stage 2:
      • Decreased inflammation compared to early stage
      • Little to no ductular proliferation
      • Varying degrees of elastosis
    • Stage 3:
      • Nodular elastosis with marked elastin deposition
      • Entrapped portal tracts and central veins
      • Mild cellularity with small bland cells
        • No atypia or mitoses
    • Stage 4:
      • Nodular elastosis with dense fibrosis
      • Small, scattered islands of hepatocytes
      • Residual portal tracts
      • Variably sized biliary cysts usually at the edges of the lesion
      • Thick walled, thrombosed vessels with fibrotic change and recanalization
  • Involves only a few hepatic lobules; does not usually involve entire segments
Microscopic (histologic) images

Contributed by Naziheh Assarzadegan, M.D.

Subcapsular lesion

Abnormal thick walled blood vessels

Biliary cyst

Positive stains
Negative stains
Sample pathology report
  • Liver, wedge biopsy:
    • Segmental atrophy of the liver; no malignancy identified (see comment)
    • Comment: The patient's history of a 5.9 cm partially exophytic, solid lesion in the right hepatic dome is noted. The lesion shows predominant sclerosis with abnormal thick walled blood vessels, entrapped hepatocytes and focal bile ductular proliferation at the periphery of the lesion. The elastic stains show focal dense network of elastic fibers in the stroma of the lesional tissue. The features taken together, including the degree of elastosis and presence of other salient features of segmental atrophy (abnormal thick walled blood vessels and focal bile ductular proliferation), are part of a spectrum of histologic features described in later stages of segmental atrophy (Am J Surg Pathol 2011;35:364).
Differential diagnosis
Board review style question #1


A 45 year old woman with history of diabetes and hypertension presents with abdominal pain and a 4.5 cm mass in the right lobe of the liver. The mass is biopsied and shows the above. What is the best diagnosis?

  1. Amyloidosis
  2. Benign biliary cyst
  3. Sclerosed hemangioma
  4. Segmental atrophy
Board review style answer #1
D. Segmental atrophy. The image shows lesional tissue composed of predominantly sclerosed parenchyma with abnormal thick walled blood vessels. Elastin stain highlights the increased elastic fibers.

Comment Here

Reference: Segmental atrophy
Board review style question #2
What stain would be the most helpful in diagnosing segmental atrophy of the liver?

  1. CD34
  2. Congo red
  3. Elastin stain
  4. Trichrome
Board review style answer #2
C. Elastin stain is helpful in identifying the elastic fibers and excluding other differentials.

Comment Here

Reference: Segmental atrophy
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