Imaging diagnosis--spinal cord chondrosarcoma associated with spirocercosis in a dog.

A 7-year-old neutered female Boerboel cross was examined for progressive left pelvic limb lameness. There was no left patellar reflex but the remaining pelvic limb reflexes were hyperreflexic. Radiographically, there was a poorly mineralized opacity occupying the intervertebral foramen at LA-L5. On computed tomography images there was a hyperattenuating intramedullary lesion at LA-L5 that continued caudally, lateralized to the left and became extramedullary, terminating at L5-L6. In addition, well marginated, hyperattenuating lesions were noted at two muscular sites. The dog underwent euthanasia and a caudal esophageal mass was found at post mortem examination. The tumors in the spinal cord, the esophagus, and the skeletal muscles were diagnosed histologically as low-grade chondrosarcoma undergoing endochondral ossification. Spirocerca lupi-induced esophageal chondrosarcoma was believed to be the primary site from which the other, presumably metastatic, lesions originated.