Fibrosarcoma of bone in the dog and cat

Fibrosarcoma of the bone is a rare malignancy accounting for about 5% of bone tumours. The mean age of subjects at onset of the tumour is 8.4 years. Fibrosarcoma develops in dogs weighing over 25 kg; no breed or gender predisposition has been reported. Tumours have been described in the appendicular bones (30%) (Fig. 1), in the oral cavity and the nasal cavities.The real existence of fibrosarcoma has been questioned because it is difficult to distinguish histologically from fibroblastic osteosarcoma, particularly when the evaluations are carried out on small specimens. The diagnosis must, therefore, be made after examining several specimens taken from the whole segment of bone resected.

Surgery with excision of wide margins can be curative even though this is a tumour that metastasises, particularly to the heart, pericardium, skin and bone, as well as to the lungs. There is no evidence that adjuvant chemotherapy improves survival._^1,2

Fibrosarcoma of the bone is the second most frequent primary bone tumour in cats. If resected completely, survival can be prolonged, without requiring chemotherapy.

References

1. AblinL.W., Berg, J., Schelling, S.H., 1991. Fibrosarcoma of the canine appendicular skeleton. Journal of American Animal Hospital Association 27(3),303-309.
2. Liptak, J.M., Kamstock, D.A., Dernell, W.S., Monteith, G.J., Rizzo, S.A., Withrow S.J., 2008. Oncologic outcome after curative-intent treatment in 39 dogs with primary chest wall tumors (1992-2005). Veterinary Surgery37(5),488-96.