Veterinary Society of
Surgical Oncology

General Considerations

  • sites: skin, subcutis, and oral cavity
  • low-grade histology: increased collagen content and low mitotic figures
  • high-grade histology: very cellular with closely packed spindle-shaped fibroblasts with many mitotic figures
  • histologically low-grade, biologically high-grade FSA is a variant in the oral cavity that tends to grow to a large size and invade into deeper structures including bone
  • distant metastasis in up to 20%
  • low-grade FSA can be difficult to differentiate histologically from fibroma, nodular fasciitis, aggressive fibromatosis, and chronic inflammatory reactions

Feline Fibrosarcoma

  • 12%-15% of feline skin tumors
  • multiple FSA in cats with feline sarcoma virus (FeSV) infection
  • FeSV will not cause neoplasia alone, not transmitted horizontally and requires FeLV for replication
  • FeSV is not associated with solitary FSA of older cats

See Vaccine-Associated and Soft Tissue Sarcomas for more information


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