Osteoblastoma of the spine. A review of 75 cases. Clinical and radiologic features of 75 cases of osteoblastoma of the spine were reviewed. In addition to pain, which was the most frequent complaint, 18 patients demonstrated objective neurologic deficit, while scoliosis was observed in 17 patients. Aspirin yielded pain relief in 13 patients. Pathologic fracture was not encountered. The radiologic and histologic characteristics of osteoblastoma of the spine are indistinguishable from those arising in other sites. The typical lesion exhibited a well-defined, geographic margin with a sclerotic, frequently lobulated border. Approximately one half of the cases were predominantly lucent, the remainder displaying varying degrees of matrix mineralization. Distribution of the osteoblastomas through the spinal axis was as follows: cervical-29, thoracic-16, lumbar-17, sacral-13. Other significant findings included posterior element involvement in 73 of 75 cases, and a striking male to female ratio of 2.5 to 1. 