Histology Course S XII 3 Department of Pathology, University of Zurich Histology Course

S XII 3 keratinizing squamous cell carcinoma of the skin HE  
  ICD-10: C44.9; ICD-O: 8071/3

67-year-old patient with immunosuppression.  Biopsy of squamous cell carcinoma of the forehead. Previous squamous epithelial carcinoma elsewhere.

skin excision with central substance defect, up to 0.3cm in diameter

Microscopically :
- The  epidermis is elevated and focally ulcerated by the tumour.
- There are signs of malignancy.
- The dermis is infiltrated.
- Cells and nuclei are distinctly polymorph, the nuclei are enlarged and hyperchromatic with prominent nucleoli.
- Numerous, partly atypical mitosescan be seen.
- Signs of differentiation: evidence of keratinisation (dyskeratotic cells) and intercellular bridges. The bordering epidermis shows actinic damage (epithelial atypia, elastoid degeneration).