Squamous-cell carcinoma

Author: Mikael Häggström
Squamous-cell carcinoma (SCC):

Locations

Use the location-specific article when applicable:

• Squamous-cell carcinoma of the skin
• Squamous-cell carcinoma of the lung
• Urinary bladder: Urothelial versus squamous-cell carcinoma
• Cervix uteri: Cervical dysplasia

Microscopic evaluation

• On high magnification, SCC is characterized by intercellular bridges and keratin formation (one focus seen at upper right)
  On high magnification, SCC is characterized by intercellular bridges and keratin formation (one focus seen at upper right)
• Typical well-differentiated nests have cells with abundant eosinophilic cytoplasm. Keratinizing centers are seen as well.
  Typical well-differentiated nests have cells with abundant eosinophilic cytoplasm. Keratinizing centers are seen as well.

To support the diagnosis of a suspected squamous-cell carcinoma, immunohistochemistry can be used, including p63 and p40.

Degree of differentiation

• Well-differentiated (and yet invasive) SCC, showing prominent keratinization and may form “pearllike” structures where dermal nests of keratinocytes attempt to mature in a layered fashion. Well-differentiated SCC has slightly enlarged, hyperchromatic nuclei with abundant amounts of cytoplasm. Intercellular bridges will frequently be visible.[1]
  Well-differentiated (and yet invasive) SCC, showing prominent keratinization and may form “pearllike” structures where dermal nests of keratinocytes attempt to mature in a layered fashion. Well-differentiated SCC has slightly enlarged, hyperchromatic nuclei with abundant amounts of cytoplasm. Intercellular bridges will frequently be visible.
• Moderately differentiated lesions of invasive SCC show much less organization and maturation with significantly less keratin formation.[1]
  Moderately differentiated lesions of invasive SCC show much less organization and maturation with significantly less keratin formation.
• Poorly differentiated, where attempts at keratinization are often no longer evident. This is a clear-cell squamous cell carcinoma. The dysplastic cells here infiltrate in cords through the dermis. Poorly differentiated SCC has greatly enlarged, pleomorphic nuclei demonstrating a high degree of atypia and frequent mitoses.[1]
  Poorly differentiated, where attempts at keratinization are often no longer evident. This is a clear-cell squamous cell carcinoma. The dysplastic cells here infiltrate in cords through the dermis. Poorly differentiated SCC has greatly enlarged, pleomorphic nuclei demonstrating a high degree of atypia and frequent mitoses.
• Poorly differentiated clear-cell squamous cell carcinoma. For this type of SCC, immunostains will likely be required to classify it unless other areas of the tumor show obvious squamous cell features such as seen here (keratinization in center).
  Poorly differentiated clear-cell squamous cell carcinoma. For this type of SCC, immunostains will likely be required to classify it unless other areas of the tumor show obvious squamous cell features such as seen here (keratinization in center).

Further workup

Immunohistochemistry for p16 highly correlates with HPV infection, and is indicated mainly in cervical dysplasia, but also in SCC of other sites where HPV infection is more or less frequently implicated, including vagina, vulva, penis, anus, tonsil and other oropharyngeal locations.

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