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W3 Histopathology

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Histopathology III: Benign Epithelial Pathoses and Potentially Malignant Disorders1

A/Prof Omar Kujan

Contents2

  • Glossary of terms used in histopathological diagnosis of premalignant lesions

Pathological Changes in Epithelium3

Pathological change in the overall structure of an epithelium can be described as:

  • a) acanthosis
  • b) atrophy
  • c) keratosis
  • e) orthokeratosis
  • f) parakeratosis

Atrophy456

Photomicrograph showing atrophic oral epithelium. The thickness of the epithelium is reduced and often the rete pegs are lost

Orthokeratosis78910

Photomicrograph showing orthokeratosis of an epithelium - the superficial cell layers are increased in thickness, the cells are flattened and have no nuclei, the layer stains bright pink. Note the granular layer in the superficial keratinocytes (arrowed), this is a feature of orthokeratosis

Parakeratosis11

Photomicrograph showing parakeratosis of an epithelium - the superficial cell layers are increased in thickness, the cells are often flattened and contain pyknotic (dark condensed, arrowed) nuclei, the layer stains bright pink

Oral Epithelial Dysplasia1213

Dysplasia Grading

WHO 2022 Classification14

  • 3-Tier System:

    • Mild Dysplasia
    • Moderate Dysplasia
    • Severe Dysplasia

  • 2-Tier System:

    1. Low grade oral epithelial dysplasia
    2. High grade oral epithelial dysplasia

Architectural Changes15

  1. Irregular epithelial stratification
  2. Loss of polarity of basal cells
  3. Drop-shaped rete ridges
  4. Increased number of mitotic figures
  5. Abnormally superficial mitoses
  6. Premature keratinisation in single cells
  7. Keratin pearls within rete ridges
  8. Loss of epithelial cohesion

Cytological Changes16

  1. Abnormal variation in nuclear size
  2. Abnormal variation in nuclear shape
  3. Abnormal variation in cell size
  4. Abnormal variation in cell shape
  5. Increased Nuclear-cytoplasmic ratio
  6. Increased nuclear size
  7. Atypical mitoses
  8. Increase number and size of nucleoli
  9. Hyperchromatism

Reference Study: Evaluation of a New Binary Grading System17

Oral Oncology (2006) 42, 987–993

journal homepage: http://intl.elsevierhealth.com/journals/oron/

Evaluation of a new binary system of grading oral epithelial dysplasia for prediction of malignant transformation

Omar Kujana, Richard J. Olivera, Ammar Khattabb, Stephen A. Robertsc, Nalin Thakkera, Philip Sloana,*

  • aSchool of Dentistry, The University of Manchester, Manchester M15 6FH, United Kingdom
  • bTrafford General Hospital Trust, Manchester, United Kingdom
  • cBiostatistics Group, The University of Manchester, Manchester M15 6FH, United Kingdom

Binary System Criteria18

  • Low-grade lesion

    • <4 architecture changes
    • <5 cytological changes

  • High-grade lesion

    • ≥4 architecture changes
    • ≥5 cytological changes

Key Histological Features of Dysplasia192021

  • Orthokeratinisation

  • Mitotic activity

  • Loss polarity of basal cells

  • Individual cell keratinisation

  • Drop shaped rete ridges

  • Mitotic activity

Histological Variation in Dysplastic Lesions22232425262728

The severity of the dysplasia may vary considerably over the lesion as may also the histological features. The following photomicrographs illustrate a large dysplastic lesion of the palate and the histological variation that is encountered between different parts of the lesion.

Blocks taken for histopathology

Footnotes

  1. Original PDF page 1: W3 IntrotoHistoapthology, p.1 ↩

  2. Original PDF page 2: W3 IntrotoHistoapthology, p.2 ↩

  3. Original PDF page 3: W3 IntrotoHistoapthology, p.3 ↩

  4. Original PDF page 4: W3 IntrotoHistoapthology, p.4 ↩

  5. Original PDF page 5: W3 IntrotoHistoapthology, p.5 ↩

  6. Original PDF page 6: W3 IntrotoHistoapthology, p.6 ↩

  7. Original PDF page 7: W3 IntrotoHistoapthology, p.7 ↩

  8. Original PDF page 8: W3 IntrotoHistoapthology, p.8 ↩

  9. Original PDF page 9: W3 IntrotoHistoapthology, p.9 ↩

  10. Original PDF page 10: W3 IntrotoHistoapthology, p.10 ↩

  11. Original PDF page 11: W3 IntrotoHistoapthology, p.11 ↩

  12. Original PDF page 12: W3 IntrotoHistoapthology, p.12 ↩

  13. Original PDF page 13: W3 IntrotoHistoapthology, p.13 ↩

  14. Original PDF page 14: W3 IntrotoHistoapthology, p.14 ↩

  15. Original PDF page 15: W3 IntrotoHistoapthology, p.15 ↩

  16. Original PDF page 16: W3 IntrotoHistoapthology, p.16 ↩

  17. Original PDF page 17: W3 IntrotoHistoapthology, p.17 ↩

  18. Original PDF page 18: W3 IntrotoHistoapthology, p.18 ↩

  19. Original PDF page 19: W3 IntrotoHistoapthology, p.19 ↩

  20. Original PDF page 20: W3 IntrotoHistoapthology, p.20 ↩

  21. Original PDF page 21: W3 IntrotoHistoapthology, p.21 ↩

  22. Original PDF page 22: W3 IntrotoHistoapthology, p.22 ↩

  23. Original PDF page 23: W3 IntrotoHistoapthology, p.23 ↩

  24. Original PDF page 24: W3 IntrotoHistoapthology, p.24 ↩

  25. Original PDF page 25: W3 IntrotoHistoapthology, p.25 ↩

  26. Original PDF page 26: W3 IntrotoHistoapthology, p.26 ↩

  27. Original PDF page 27: W3 IntrotoHistoapthology, p.27 ↩

  28. Original PDF page 28: W3 IntrotoHistoapthology, p.28 ↩

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