Lung
Squamous cell carcinoma
Squamous cell carcinoma
Author: Deepali Jain, M.D.
Last author update: 1 September 2012
Last staff update: 8 May 2023 (update in progress)
Copyright: 2003-2023, PathologyOutlines.com, Inc.
PubMed Search: squamous cell carcinoma[title] lung
Table of Contents
Definition / general | Terminology | Case reports | Gross description | Gross images | Microscopic (histologic) description | Microscopic (histologic) images | Cytology description | Positive stains | Negative stains | Electron microscopy description | Differential diagnosisCite this page: Jain D. Squamous cell carcinoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/lungtumorSCC.html. Accessed May 30th, 2023.
Definition / general
- Carcinoma arising from squamous epithelial cells, morphologically characterized by proliferation of atypical, often pleomorphic squamous cells; graded as well, moderately, or poorly differentiated; well differentiated carcinomas are usually associated with keratin production and presence of intercellular bridges between adjacent cells; subtypes include basaloid, clear cell type, papillary, small cell nonkeratinizing
Terminology
- Early lung carcinoma of hilar type:
- Arises proximal to sub segmental bronchi (i.e. major bronchi), confined to bronchial wall with no lymph node metastases
- Usually squamous cell carcinoma; may be polypoid, nodular, superficially infiltrating or mixed
- Longitudinal mucosal folds show changes at tumor border
- Superficial tumor has thickened and fused folds
- Five year survival is 90% or more if no second squamous cell carcinoma present
- Early squamous cell carcinoma of peripheral type:
- Defined as tumor 2 cm or less in peripheral lung with no lymph node or distal metastases
- Only rarely identified in practice, since these tumors grow rapidly
- Often have glandular cell characteristics
- Basaloid squamous cell carcinoma:
- Very aggressive subtype
- Spindle cell squamous cell carcinoma:
- Also called sarcomatoid carcinoma
- Papillary squamous cell carcinoma:
- Rare, well differentiated squamous cell carcinoma characterized by papillary, exophytic growth pattern and hyperkeratosis
Case reports
- 75 year old woman with papillary endobronchial squamous cell carcinoma (Ann Diagn Pathol 2005;9:284)
Gross description
- Usually central portion of lung affecting larger bronchi but may be peripheral
- Invades peribronchial soft tissue, lung parenchyma and nearby lymph nodes
- May compress pulmonary artery and vein
- Peripheral tumors often have nodular growth with central necrosis and cavitation
- Surrounding lung may exhibit lipid pneumonia, bronchopneumonia, atelectasis
- Calcification is unusual
Gross images
Contributed by @yro854 on Twitter
Squamous cell carcinoma
Images hosted on other servers:
Central cavitation
Tumor obstructing bronchus
Tumor extending to pleura
Microscopic (histologic) description
- Sheets or islands of large polygonal malignant cells containing keratin (individual cells or keratin pearls) and intercellular bridges
- Adjacent bronchial dysplasia or carcinoma in situ is common
- At advancing tumor border, tumor cells usually destroy alveoli or fill alveolar spaces
- Rarely spreads beneath basement membrane
- May have focal areas of intracytoplasmic mucin
- Rarely oncocytes, foreign body giant cells (reacting to keratin), pallisading granulomas, extensive neutrophilic infiltration, lepidic growth pattern at tumor periphery, clear cell change (glycogen)
- Classify as well, moderately or poorly differentiated based on amount of keratinization present in predominant component
- Peripheral tumor types: alveolar space filling (tumor cells fill alveoli but don’t destroy elastic septa), expanding type (growth destroys elastic septa) or mixture
- Subtypes: basaloid, clear cell (numerous clear tumor cells containing glycogen), small cell (small tumor cells with focal keratinization, distinct nucleoli, sharply outlined tumor nests, less necrosis than small cell neuroendocrine carcinoma), papillary
- Important to examine margins carefully for intraepithelial spread
Microscopic (histologic) images
Contributed by Andrey Bychkov, M.D., Ph.D.
Bronchial biopsy
SCC cocktail
Images hosted on other servers:
Well differentiated
Moderately differentiated
Mixed, with keratin pearls and mitotic figures
Cytology description
- Often positive in sputum
Positive stains
- p63 most common (Arch Pathol Lab Med 2012;136:155, Hum Pathol 2002;33:921); also CK5/6 (87-100%), EMA, thrombomodulin (87-100%)
- Variable CD15, CEA, HPV, mesothelin (16-31%), p53, p40, S100
Negative stains
- Vimentin (usually), TTF1 (usually), Napsin A
Electron microscopy description
- Abundant tonofilaments, complex desmosomes, basal lamina
Differential diagnosis
- Squamous metaplasia with atypia (Hum Pathol 2002;33:1052)
