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Invasive carcinoma versus pseudoinvasion: interobserver variability in the assessment of left-sided colorectal polypectomies
  1. Michael Lee1,
  2. Satoru Kudose1,
  3. Armando Del Portillo1,
  4. Huaibin Mabel Ko2,
  5. Hwajeong Lee3,
  6. Meredith E Pittman4,
  7. Marcela A Salomao5,
  8. Antonia R Sepulveda1,
  9. Stephen M Lagana1
  1. 1Department of Pathology and Cell Biology, Columbia University Medical Center, New York City, New York, USA
  2. 2Department of Pathology and Laboratory Medicine, Icahn School of Medicine, New York City, New York, USA
  3. 3Department of Pathology and Laboratory Medicine, Albany Medical Center, Albany, New York, USA
  4. 4Department of Pathology and Laboratory Medicine, Weill Cornell Medical Center, New York City, New York, USA
  5. 5Department of Laboratory Medicine and Pathology, Mayo Clinic, Phoenix, Arizona, USA
  1. Correspondence to Dr Michael Lee, Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY 10032, USA; mjl2197{at}cumc.columbia.edu

Abstract

Objectives Misplaced epithelium in adenomas can occasionally be difficult to distinguish from invasive adenocarcinoma. We evaluated interobserver variability in the assessment of left-sided colon polypectomies for pseudoinvasion versus invasive adenocarcinoma and further investigated relevant histological findings.

Methods 28 consecutive left-sided colon polyps with the keywords “pseudoinvasion”, “epithelial misplacement”, “herniation”, “prolapse” or “invasive adenocarcinoma” were collected from 28 patients and reviewed by eight gastrointestinal pathologists. Participants assessed stromal hemosiderin, lamina propria/eosinophils surrounding glands, desmoplasia, high grade dysplasia/intramucosal adenocarcinoma and margin status and rendered a diagnosis of pseudoinvasion, invasive adenocarcinoma, or both.

Results Agreement among pathologists was substantial for desmoplasia (κ=0.70), high grade dysplasia/intramucosal adenocarcinoma (κ=0.66), invasive adenocarcinoma (κ=0.63) and adenocarcinoma at the margin (κ=0.65). There was moderate agreement for hemosiderin in stroma (κ=0.53) and prolapse/pseudoinvasion (κ=0.50). Agreement was low for lamina propria/eosinophils around glands (κ=0.12). For invasive adenocarcinoma, seven or more pathologists agreed in 24 of 28 cases (86%), and there was perfect agreement in 19/28 cases (68%). For pseudoinvasion, seven or more pathologists agreed in 19 of 28 cases (68%), and there was perfect agreement in 16/28 cases (57%).

Conclusion Moderate to substantial, though imperfect, agreement was achieved in the distinction of pseudoinvasion from invasive carcinoma.

  • carcinoma
  • colon
  • colorectal neoplasms
  • intestine
  • large

Data availability statement

All data relevant to the study are included in the article.

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Data availability statement

All data relevant to the study are included in the article.

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Footnotes

  • Handling editor Runjan Chetty.

  • Contributors All authors except for SK reviewed the digital slides, provided diagnostic assessments and contributed to writing the manuscript. SK performed the statistical analysis and created tables and scatterplots.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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