Vertebral Telangiectatic Osteosarcoma in a Dog: MRI and Computed Tomography Findings and Outcome.

A vertebral telangiectatic osteosarcoma was diagnosed in a 5 yr old female neutered Staffordshire bull terrier presenting with paraplegia with nociception in one limb and absent on the other. Computed tomography revealed a hypoattenuating, osteolytic lesion affecting the T9 vertebra. MRI revealed a well-demarcated dorsal extradural mass overlying the spinal cord along the T8-T10 vertebral bodies. A hemorrhaging, reddish mass dorsal to the spinal cord was removed surgically, and a diagnosis of telangiectatic osteosarcoma was confirmed through histopathological examination. The dog improved following surgery and chemotherapy but suffered acute deterioration 5 wk postoperatively and was euthanized. This is the first reported case of a vertebral telangiectatic osteosarcoma where computed tomography and MRI sequences were obtained, with surgical extraction and medical chemotherapy. This subtype of osteosarcoma is believed to have a negative prognosis in dogs, although this is the first report of attempted surgical treatment. Telangiectatic osteosarcoma should be considered as a differential in dogs, particularly when a mass is identified with associated intralesional hemorrhagic spaces, commonly seen in the telangiectatic subtype. Currently, there are no established treatment options for vertebral telangiectatic osteosarcomas and the prognosis appears to be poor.