Thyroid gland
Other carcinoma
Squamous cell carcinoma

Author: Shuanzeng Wei, M.D., Ph.D. (see Authors page)
Editor: Zubair W. Baloch, M.D., Ph.D.

Revised: 19 September 2016, last major update September 2016

Copyright: (c) 2002-2016,, Inc.

PubMed Search: Squamous cell carcinoma [title] thyroid [title]

Cite this page: Squamous cell carcinoma. website. Accessed October 23rd, 2016.
Definition / General
  • Very rare, highly lethal thyroid carcinoma with pure squamous component
  • Clinically and pathologically shares features with anaplastic thyroid cancers; can be regarded as a variant of anaplastic thyroid carcinoma
  • Must rule out:
    • Metastasis or direct invasion of squamous cell carcinoma from oropharynx, larynx, trachea, lung, other organs
    • Papillary carcinoma with foci of squamous differentiation (occurs in 15% to 45% of papillary carcinomas)
    • Anaplastic thyroid carcinoma with squamous differentiation
    • Other thyroid carcinomas with squamous differentiation, including mucoepidermoid carcinoma, sclerosing mucoepidermoid carcinoma with eosinophilia, CASTLE
Essential Features
  • Squamous cell carcinoma is regarded as a variant of anaplastic thyroid carcinoma
  • Aggressive clinical behavior
  • Similar to anaplastic carcinoma, affects older patients with chronic goiter
Clinical Features
  • Older patients present with a rapidly enlarging neck mass
  • Patients may have a long history of preexisting thyroid disease
  • Extrathyroidal extension and cervical nodal metastases are common, distant metastases are rare
Prognostic Factors
  • Poor prognosis with median survival < 6 months
  • Death in almost all cases, usually due to local progression (Int Semin Surg Oncol 2007;4:8) or airway compression
Case Reports
  • Radical resection and radiation (often radioresistant)
Clinical Images

Images hosted on other servers:

Mass pressuring and
infiltrating trachea and
surrounding soft tissue

Ulceroproliferative growth

Recurrent ulceroproliferative growth

Gross Description
  • Firm infiltrating mass with necrosis
Gross Images

Images hosted on other servers:

Enlarged left lobe

White tumor with central necrosis

Micro Description
  • Invasive squamous carcinoma, with or without keratinization
  • High mitotic index
  • Extrathyroid, vascular and perineural invasions are common
Micro Images

Images hosted on PathOut servers:

Squamous cell carcinoma with necrosis, courtesy of Shuanzeng Wei, M.D., Ph.D.

Images hosted on other servers:

Infiltrating squamous cell carcinoma

Cytology Images

Images hosted on other servers:

Atypical squamoid cell

Positive Stains
Differential Diagnosis
  • CASTLE: circumscribed, slowly growing tumor, CD5+, CD117+
  • Metastasis or direct invasion of squamous cell carcinoma from other organs: history of squamous cell carcinoma, PAX8-
  • Papillary thyroid carcinoma with squamous differentiation: squamous component is small portion of the well differentiated thyroid carcinoma
  • Squamous metaplasia: benign squamous cells