Radiation therapy is also used as adjunct treatment, but its effectiveness is controversial. Chemotherapy may be used with high-grade and dedifferentiated chondrosarcomas. Ewing Sarcoma and PNET Ewing sarcoma and PNET are pathologically distinct entities with very similar characteristics clinically and radiologically. In fact, no radiologic differences have been described, to the best of our knowledge, and their imaging appearances are therefore discussed together. However, metastatic foci of Ewing sarcoma and PNET involving the spine are much more common than primary lesions.
Clinical symptoms are pain and neurologic changes, including loss of bowel and bladder function.
The lesions are typically centered in the vertebral body, although extension into the posterior elements is not uncommon. Histologically, both Ewing sarcoma and PNET are composed of small, round, blue cells, with large irregular sheets of cells divided by septa, scant cytoplasm, and abundant collagen. Immunohistochemical studies are needed to distinguish Ewing sarcoma from PNET, with the latter being characterized by neural differentiation. CT and particularly MR imaging demonstrate osseous and surrounding soft-tissue involvement to best advantage. Paraspinal soft-tissue masses are often a prominent feature of these lesions.