Squamous Cell Carcinoma



Squamous Cell Carcinoma







Key Facts


Terminology



  • Malignant epithelial neoplasm with squamous (epidermoid) differentiation


Macroscopic Features



  • Central or peripheral tumors


  • White or light brown in color with homogeneous cut surface; cut surface may show areas of hemorrhage &/or necrosis


  • Tumors may be predominantly cystic


  • Tumor size may vary from 2 cm to > 10 cm in diameter


Microscopic Pathology



  • Solid


  • Cystic


  • Spindled


Top Differential Diagnoses



  • Small cell carcinoma



    • In cases of small cell variant of squamous cell carcinoma, may be able to identify in situ squamous component


    • Chromatin pattern of small cell carcinoma, “salt and pepper,” not present in small cell variant of squamous cell carcinoma


  • Sarcoma



    • In spindle cell variant of squamous cell carcinoma, may identify residual focal areas of squamous differentiation


  • Large cell neuroendocrine carcinoma



    • In cases of basaloid squamous cell carcinoma, large cell neuroendocrine carcinoma may enter the differential diagnosis






Gross photograph of squamous cell carcinoma of the lung shows a centrally located large neoplasm. The tumor has a soft consistency and focal areas of necrosis image.






Keratinizing well-differentiated squamous cell carcinoma. Note the presence of keratin formation, characteristic of well-differentiated tumors image.


TERMINOLOGY


Synonyms



  • Epidermoid carcinoma


Definitions



  • Malignant epithelial neoplasm with squamous (epidermoid) differentiation


ETIOLOGY/PATHOGENESIS


Environmental Exposure



  • Associated with tobacco smoke


CLINICAL ISSUES


Presentation



  • Cough


  • Shortness of breath


  • Hemoptysis


  • Chest pain


Treatment



  • Surgical approaches



    • Wedge resection


    • Lobectomy


    • Pneumonectomy


  • Radiation



    • Chemotherapy or radiation therapy


Prognosis



  • Depends on stage at time of diagnosis


MACROSCOPIC FEATURES


General Features



  • Central or peripheral tumors


  • White or light brown in color with homogeneous cut surface


  • Cut surface may show areas of hemorrhage &/or necrosis


  • Tumors may be predominantly cystic


  • Tumor size may vary from 2 cm to > 10 cm in diameter


MICROSCOPIC PATHOLOGY


Histologic Features



  • Keratinization


  • Keratin pearls


  • Intercellular bridges


Predominant Pattern/Injury Type



  • Solid


  • Cystic


  • Spindled


Predominant Cell/Compartment Type



  • Epithelial, squamous


DIFFERENTIAL DIAGNOSIS


Small Cell Carcinoma



  • In cases of small cell variant of squamous cell carcinoma, the presence of an in situ squamous component will be helpful for diagnosis


  • Chromatin pattern of small cell carcinoma (“salt and pepper”) not present in small cell variant of squamous cell carcinoma


  • May show positive staining for neuroendocrine markers and TTF-1


Sarcoma



  • May identify residual focal areas of squamous differentiation in spindle cell variant of squamous cell carcinoma



  • Immunohistochemical markers for mesenchymal origin may prove useful


Large Cell Neuroendocrine Carcinoma



  • In cases of basaloid squamous cell carcinoma, large cell neuroendocrine carcinoma may enter the differential diagnosis


  • Basaloid squamous cell carcinoma is negative for neuroendocrine markers


  • Immunomarkers for neuroendocrine origin will show positive staining


DIAGNOSTIC CHECKLIST


Pathologic Interpretation Pearls



  • Presence of keratinization, keratin pearls, &/or intercellular bridges


GRADING


Well-differentiated Squamous Cell Carcinoma



  • Tumor shows obvious keratinization, and at high-power view, intercellular bridges are apparent


Moderately Differentiated Squamous Cell Carcinoma

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Jul 9, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Squamous Cell Carcinoma

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