Squamous dysplasia of the head and neck

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Squamous dysplasia of the head and neck, often squamous dysplasia, is a precursor to head and neck squamous cell carcinoma.

General

Gross

Features:[1]

Microscopic

Features:

  • Basal nuclear atypia - may be mild.
  • Lack of maturation to the surface.
  • +/-Parakeratosis.

DDx:

Grading

  • Numerous grading systems exist.[2]

WHO system

The 2005 "blue book" system - as summarized by Gale et al.:[2]

  • Mild dysplasia.
  • Moderate dysplasia.
  • Severe dysplasia.
  • Carcinoma in situ.

Ljubljana system

As per Gale et al.:[3]

  • Low-grade SIL.
  • High-grade SIL.
  • Carcinoma in situ.

Low-grade squamous intraepithelial lesion:[3]

  • Increased prickle cell layer.
  • +/-Thickening of basal and/or parabasal cell layers.
  • No significant nuclear atypia.
  • Rare mitotic figures.
  • Dyskeratotic cells - rare.
  • Must show maturation to surface.

High-grade squamous intraepithelial lesion:[3]

  • Long axis perpendicular to basement membrane.
  • Lower half or more abnormal.
  • Nuclear pleomorphism present.
    • Irregular nuclear contours.
    • Hyperchromasia.
    • Nucleoli increased in size and number.
  • Increased NC ratio.
  • Mitotic activity in predominantly in the lower 2/3 of the epithelium.
  • Dyskeratotic cell common.

Carcinoma in situ:[3]

  • "Full thickness" loss of stratification.
    • May have thin layer of compressed-appearing cells (3-5 cells thick) with their long axes parallel to the basement membrane.
  • Nuclear pleomorphism present.
    • Irregular nuclear contours.
    • Hyperchromasia.
    • Nucleoli increased in size and number.
  • Increase mitotic activity.
    • Atypical mitoses common.
  • Dyskeratotic/apoptotic cells typically very common.

Negatives:

Subtypes:

  • Basal cell type.
    • Non-eosinophilic cytoplasm.
    • No apparent intercellular bridges (prickles).
    • Long axis of cells perpendicular to the basement membrane.
    • Typically non-keratinizing.
  • Spinous cell type.
    • Intercellular bridges (prickles) present.
    • Eosinophilic cytoplasm.
    • Typically keratinizing.

Images

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PHARYNGEAL WALL, POSTERIOR, BIOPSY:
- SQUAMOUS MUCOSA WITH MILD SQUAMOUS DYSPLASIA.
- NEGATIVE FOR MALIGNANCY.

See also

References

  1. ↑ 1.0 1.1 Eversole, LR. (Mar 2009). "Dysplasia of the upper aerodigestive tract squamous epithelium.". Head Neck Pathol 3 (1): 63-8. doi:10.1007/s12105-009-0103-8. PMID 20596993.
  2. ↑ 2.0 2.1 Gale, N.; Zidar, N.; Poljak, M.; Cardesa, A. (Mar 2014). "Current views and perspectives on classification of squamous intraepithelial lesions of the head and neck.". Head Neck Pathol 8 (1): 16-23. doi:10.1007/s12105-014-0530-z. PMID 24595419.
  3. ↑ 3.0 3.1 3.2 3.3 Gale, N.; Blagus, R.; El-Mofty, SK.; Helliwell, T.; Prasad, ML.; Sandison, A.; Volavšek, M.; Wenig, BM. et al. (Oct 2014). "Evaluation of a new grading system for laryngeal squamous intraepithelial lesions-a proposed unified classification.". Histopathology 65 (4): 456-64. doi:10.1111/his.12427. PMID 24689850.
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