Veterinary Society of
Surgical Oncology

General Considerations

  • 2 forms: single (= osteochondroma) or multicentric (= osteochondromatosis)
  • multiple cartilaginous exostoses occurs after skeletal maturity in cats
  • mean age 3.2 years
  • no breed or sex predisposition ± Siamese cats
  • etiology: familial or viral with nearly all cats are FeLV-positive)
  • multiple cartilaginous exostoses are rarely symmetrical and do not affect long bones, in contrast to dogs
  • common sites: scapula, vertebrae, and mandible
  • FeLV-induced multiple cartilaginous exostoses are rapidly progressive with firm, painful swellings
  • survey radiographs: sessile or pedunculated protuberances from bony surfaces with indistinct borders, loss of smooth contour, and evidence of lysis, particularly with malignant transformation
  • lesions are composed of hard irregular exostoses with a fibrous and cartilaginous cap
  • endochondral ossification extends from the cap for a variable thickness
  • complete surgical resection is difficult as the cap tends to blend with adjacent tissue
  • surgery is indicated for palliation but recurrence is common
  • multiple cartilaginous exostoses have an aggressive biologic behaviour with potential for malignant transformation and metastases
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