Osteosarcoma
From Felipedia
Although rare, osteosarcoma are the most frequent type of bone cancer that affects all breeds of cats, with males more highly represented. There is no age predisposition, with the cancer occurring from 12 months of age onwards.
The long bones (femur/humerus) are more often affected in younger cats (3-5 years old), but osteosarcomas can also be found affecting the mandible/maxilla bones of the jaw in geriatric cats. Subcutaneous variants can form as a result of feline fibrosarcoma complex.
Clinical signs
Acute onset lameness in the affected limb, often associated with swelling in the region of the bone growth. There is no breed predilection, although males are more represented than females. Clinically, those cases of osteosarcoma involving the limbs show swelling and pain in the area of tumour growth; there is limitation of motion of the associated joint, and progressive muscle atrophy results from disuse of the limb. Tumours arising from flat bones show swelling of the affected area. Those arising from the mandible and maxilla often produce difficulty in chewing. Those arising from the nasal bones produce a discharge from the nostrils. Vertebral involvement often manifests itself as neurologic symptoms. Involvement of the pelvic bones causes difficulty in defecation due to narrowing of the diameter of the pelvis. Grossly the tumour may be firm or soft, depending on the amount of tumour bone being produced. The lesions are usually invasive and greyish white. Histologically, the tumour cells are fusiform and epithelioid, show marked pleomorphism and mitotic activity, and have an interwoven pattern. Variable amounts of tumour osteoid and bone are produced, but malignant cartilage is found infrequently[1].
Treatment
Metastasis is less common in the cat than in the dog; metastases originate from appendicular osteosarcomas and not from those of axial origin. Metastasis, when it occurs, is by the hematogenous route to the lungs and internal organs; consequently there is a poor prognosis in these cases. Chemotherapy may increase survival rate in younger cats.
References
- ↑ Okada M, Kitagawa M, Nagasawa A, Itou T, Kanayama K, Sakai T. (2009) Magnetic resonance imaging and computed tomography findings of vertebral osteosarcoma in a cat. J Vet Med Sci 71(4):513-7
