Liver & intrahepatic bile ducts

Other malignancies

Hepatoblastoma-epithelial type

Topic Completed: 1 February 2012

Minor changes: 23 September 2020

Copyright: 2002-2021,, Inc.

PubMed Search: Epithelial hepatoblastoma[mh]

Deepali Jain, M.D.
Page views in 2020: 4,161
Page views in 2021 to date: 1,849
Cite this page: Jain, D. Hepatoblastoma-epithelial type. website. Accessed December 3rd, 2021.
Definition / general
  • 56% of hepatoblastomas are epithelial type

Fetal pattern (31%):
  • Tumor cells in trabeculae 2 - 3 cells thick (resembling fetal liver), separated by sinusoids lined by CD34+ endothelial cells
  • Tumor cells are same size or smaller than in nonneoplastic liver
  • Distinct cell membranes, uniform, polyhedral, slightly higher nuclear/cytoplasmic ratio, inconspicuous nucleoli and may contain bile
  • Minimal pleomorphism, no / rare mitotic figures
  • Have "dark" and "light" foci related to amount of glycogen and fat
  • Extramedullary hematopoiesis common; no portal tracts, bile ducts or ductules at the periphery
  • Reduced reticulin, rare mitosis
  • Cholangoblastic if ductular differentiation (CK7 / 19 positive) prominent
  • Crowded fetal type: crowded cells and 2+ mitotic figures/10 HPF

Embryonal pattern (19%):
  • Sheets, ribbons, rosettes, papillary patterns or trabeculae of variable thickness with immature appearance, discohesive small cells with poorly defined cell borders, basophilic cytoplasm, high N/C ratio, prominent nucleoli, coarse chromatin and increased mitotic figures
  • Extramedullary hematopoiesis, necrosis and vascular lakes are common; no fat, glycogen or bile

Macrotrabecular pattern (3%):
  • Frequent trabeculae > 10 cells thick throughout the tumor, variable cytologic features

Small cell undifferentiated / anaplastic pattern (3%):
  • Most primitive form
  • Definition: 70%+ small cell areas; however, even small foci should be reported becaues associated with poor prognosis
  • Discohesive sheets of small uniform keratin+ cells with minimal cytoplasm, indistinct cell borders, oval hyperchromatic nuclei, variable prominent nucleoli and increased mitotic figures (Mod Pathol 2003;16:930)
  • Resembles small cell carcinoma at other sites
  • May have mucoid stroma, hyalinized septae; bile
  • Loss of INI1 associated with rhabdoid phenotype
Gross images

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Epithelial hepatoblastoma

Patient with trisomy 18

Microscopic (histologic) images

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Fetal pattern

Fetal pattern in patient with trisomy 18

Small cell pattern

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