Thoracolumbar vertebral osteochondroma in a young dog.

Osteosarcoma was diagnosed in a 7-month-old female German Shepherd Dog with hind limb paresis. Radiography revealed a circumscribed calcified mass in the dorsal vertebral lamina at T13-L1 resulting in extradural compression of the spinal cord. Surgical excision of the mass resulted in gradual return to normal neurologic function. Four weeks after surgery, the dog became severely atactic after rolling onto its back. A chip fracture of T13 was identified, and the dog was euthanatized at the owners' request.