Primary bone tumors and pseudotumors of the lumbosacral spine.

Primary tumors of the spine are relatively infrequent lesions compared with metastatic disease, multiple myeloma, and lymphoma which are the more frequent neoplasms of the spine and usually manifest with multifocal lesions and thus pose little diagnostic dilemma. However, in the presence of a solitary spinal lesion, the more uncommon primary tumors of the spine represent an important group of entities for diagnostic consideration. The most common benign and malignant primary tumors of the spine are enostosis, osteoid osteoma, osteoblastoma, giant cell tumor, aneurysmal bone cyst, osteochondroma, chordoma, chondrosarcoma, Ewing sarcoma, primitive neuroectodermal tumor, and osteosarcoma. The imaging features of these lesions are often characteristic. Radiologists should be aware of the appearance of these unusual tumors in order to provide a complete differential diagnosis.