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
- 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:
- Squamous hyperplasia.
- Benign leukoplakia.
- Head and neck squamous cell carcinoma.
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.
See also
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.