Histology Course A IV 31 Department of Pathology, University of Zurich Histokurs

A IV 31

fibrous histiocytoma of the skin HE further information (German) on HiPaKu 
  ICD-10: C44.9; ICD-O: 8832/0
37-year-old female had a small brownish skin tumor excised.
- Ill-defined intradermal tumor.
- The tumor is formed by bland interlacing spindle cells located in a matrix consisting of collagen fibers.
- The borders of the lesion are infiltrative; spindle cells extend into, but do not destroy the surrounding tissue.
- In addition, histiocytes with cytoplasmic vacuoles, small hemosiderin deposits and capillaries with thickened walls are found.
- The epidermis above the tumor is hyperplastic and hyperpigmented.

The tumor is benign in its nature despite its infiltrative growth pattern. Extensive local invasion does not occur.