Squamous cell carcinoma
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This article deal with squamous cell carcinoma, also squamous carcinoma, a very common epithelial derived malignant neoplasm that can arise from many sites. It is commonly abbreviated SCC.
Sites
Skin
- A common skin tumour.
Head and neck
- Most common tumour of the head & neck.
Tumour extent
- There is no agreed upon measure tumour extent (tumour thickness/depth of invasion)[1] - proposed measures:[2]
- "Tumour thickness" = perpendicular distance from mucosal surface to deepest point of invasion.
- "Tumour depth" = perpendicular distance epithelial basement membrane to deepest point of invasion.
Uterine cervix
- Most common form of cervical cancer.
Vulva
- Most common form of vulvar cancer.
Lung
- A common form of lung cancer that is associated with smoking.
Other sites
Microscopic
Classification
SCC is subdivided by the WHO into:[3]
- Keratinizing type (KT).
- Worst prognosis.
- More common than non-keratinizing type.[4]
- Undifferentiated type (UT).
- Intermediate prognosis.
- EBV association.
- Non-keratinizing type (NT).
- Good prognosis.
- EBV association.
Features based on classification:[3]
- KT subtype:
- Keratinization & intercellular bridges through-out most of the malignant lesion.
- UT:
- Non-distinct borders/syncytial pattern.
- Nucleoli.
- NT:
- Well-defined cell borders.
Invasive squamous cell carcinoma
Features:
- Eosinophilia.
- Extra large nuclei/bizarre nuclei.
- Inflammation (lymphocytes, plasma cells).
- Long rete ridges.
- Numerous beeds/blobs of epithelial cells that seem unlikely to be rete ridges.
Pitfalls:
- Tangential cuts.
- If you can trace the squamous cells from a gland to the surface it is less likely to be invasive cancer.
Notes on invasion:
- Nice review paper by Wenig.[5]
- See SCC of the cervix versus CIN III.
Image(s):
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Subtypes
There are several subtypes:[6]
- Adenosquamous carcinoma.
- Ancatholytic squamous cell carcinoma.
- Basaloid squamous cell carcinoma - poor prognosis, usu. diagnosed by recognition of typical SCC.
- Carcinoma cuniculatum.
- Verrucous carcinoma - good prognosis, rare.
- Papillary squamous cell carcinoma.
- Lymphoepithelial carcinoma - rare.
- Spindle cell squamous carcinoma - a common spindle cell lesion of the H&N.
Verrucous squamous cell carcinoma
- AKA verrucous carcinoma.
General
- Good prognosis.
- Histomorphologically deceptively bland, i.e. non-malignant appearing.
Microscopic
Features:
- Exophytic growth.
- Well-differentiated.
- "Glassy" appearance.
- Pushing border - described "elephant feet".
DDx:
Images:
Spindle cell squamous carcinoma
General
- Common spindle cell lesion of the head and neck.
Microscopic
Feature:
- Histomorphologic key to the diagnosis: finding a component of conventional squamous cell carcinoma.
- Malignant spindle cell neoplasm.
DDx:
- Spindle cell melanoma.
- Mesenchymal neoplasm.
IHC
- Typically keratin -ve.
- p63 +ve.
Basaloid squamous cell carcinoma
- May mimic adenoid cystic carcinoma.
- Classically base of tongue.[8]
- Typically poor prognosis.
Features:
- Need keratinization. (???)
DDx:
- Neuroendocrine tumour.
Lymphoepithelial (squamous cell) carcinoma
- This is discussed in detail in the lymphoepithelioma-like carcinoma (LELC) article.
- In the head and neck this is a separate entity known as nasopharyngeal carcinoma.
General
Microscopic
Features:
- Malignant squamoid cells (eosinophilic cytoplasm, nuclear atypia).
- Abundant mononuclear inflammatory cells (plasma cells, lymphocytes).
Images: see the LELC article.
See also
References
- ↑ Pentenero, M.; Gandolfo, S.; Carrozzo, M. (Dec 2005). "Importance of tumor thickness and depth of invasion in nodal involvement and prognosis of oral squamous cell carcinoma: a review of the literature.". Head Neck 27 (12): 1080-91. doi:10.1002/hed.20275. PMID 16240329.
- ↑ URL: http://www.cap.org/apps/docs/committees/cancer/cancer_protocols/2011/LipOralCav_11protocol.pdf. Accessed on: 3 April 2012.
- ↑ 3.0 3.1 Mills, Stacey E; Carter, Darryl; Greenson, Joel K; Oberman, Harold A; Reuter, Victor E (2004). Sternberg's Diagnostic Surgical Pathology (4th ed.). Lippincott Williams & Wilkins. pp. 975. ISBN 978-0781740517.
- ↑ URL: http://www.cap.org/apps/docs/committees/cancer/cancer_protocols/2011/LipOralCav_11protocol.pdf. Accessed on: 3 April 2012.
- ↑ Wenig BM (March 2002). "Squamous cell carcinoma of the upper aerodigestive tract: precursors and problematic variants". Mod. Pathol. 15 (3): 229–54. doi:10.1038/modpathol.3880520. PMID 11904340. http://www.nature.com/modpathol/journal/v15/n3/pdf/3880520a.pdf.
- ↑ URL: http://www.cap.org/apps/docs/committees/cancer/cancer_protocols/2011/LipOralCav_11protocol.pdf. Accessed on: 3 April 2012.
- ↑ URL: http://www.juniordentist.com/verrucous-carcinoma.html. Accessed on: 3 April 2012.
- ↑ URL: http://www.biomedcentral.com/1471-2407/6/146. Accessed on: March 9, 2010.
- ↑ Skinner, NE.; Horowitz, RI.; Majmudar, B. (Oct 2000). "Lymphoepithelioma-like carcinoma of the uterine cervix.". South Med J 93 (10): 1024-7. PMID 11147469.