Squamous dysplasia of the head and neck

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

General

Similar to squamous dysplasia elsewhere.
Precursor to head and neck squamous cell carcinoma.

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:

Basement membrane intact.
- Smooth contour between epithelial layer and underlying stroma.
No stromal desmoplastic response.

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.

References

↑ ^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.
↑ ^2.0 ^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.
↑ ^3.0 ^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.

External links

Squamous dysplasia (wiki.uiowa.edu).

[pmid20596993-1] 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.

[pmid24595419-2] 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.

[pmid24689850-3] 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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