Squamous cell carcinoma

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This article deal with squamous cell carcinoma, also squamous carcinoma, and very common epithelial derived malignant neoplasm that can arise from many sites.

Sites

Head and neck

Uterine cervix

Vulva

Lung

  • A common form of lung cancer that is associated with smoking.

Other sites

Microscopic

Classification

SCC is subdivided by the WHO into:[1]

  • Keratinizing type (KT).
    • Worst prognosis.
  • Undifferentiated type (UT).
    • Intermediate prognosis.
    • EBV association.
  • Nonkeratinizing type (NT).
    • Good prognosis.
    • EBV association.

Features based on classification:[1]

  • KT subtype:
    • Keratinization & intercellular bridges through-out most of the malignant lesion.
  • UT:
    • Non-distinct borders/syncytial pattern.
    • Nucleoli.
  • NT:
    • Well-defined cell borders.

Invasion

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:

Image(s):

Subtypes

There are several subtypes:[3]

  • Basaloid - poor prognosis, usu. diagnosed by recognition of typical SCC.
  • Warty (Condylomatous).
  • Verrucous - good prognosis, rare.
  • Papillary.
  • Lymphoepithelial, rare.
  • Spindle cell, a common spindle cell lesion of the H&N.

Verrucous squamous cell carcinoma

Features:

  • Exophytic growth.
  • Well-differentiated.
  • "Glassy" appearance.
  • Pushing border.

DDx: papilloma.

Spindle cell squamous carcinoma

  • Key to diagnosis is finding a component of conventional squamous cell carcinoma.

IHC:

  • Typically keratin -ve.
  • p63 +ve.

DDx:

  • Spindle cell melanoma.
  • Mesenchymal neoplasm.

Basaloid squamous cell carcinoma

  • May mimic adenoid cystic carcinoma.
  • Classically base of tongue.[4]
  • Typically poor prognosis.

Features:

  • Need keratinization. (???)

DDx:

  • Neuroendocrine tumour.

Lymphoepithelial (squamous cell) carcinoma

  • Rare.
  • +/-EBV.

See also

References

  1. ↑ 1.0 1.1 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.
  2. ↑ 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.
  3. ↑ URL: http://www.pathconsultddx.com/pathCon/diagnosis?pii=S1559-8675%2806%2970297-2. Accessed on: March 9, 2010.
  4. ↑ URL: http://www.biomedcentral.com/1471-2407/6/146. Accessed on: March 9, 2010.
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