Background
Primary spinal tumors fall into a distinct category because their timely diagnosis and the immediate institution of treatment have an enormous impact on the patient's overall prognosis and hope for a cure. [1, 2]
Generally, with spinal pathology, problems that arise are either chronic problems related to degenerative disease or deformity or acute manifestations of traumatic sequelae. When considering tumors of the spine, one must consider the different tissue types around the spinal column. The presence of neural tissue, meningeal tissue, bone, and cartilage makes any of these tissue types a possible nidus for neoplastic change. Also, metastatic lesions may spread to the spine from distant primary tumor sites by hematogenous or lymphatic routes.
Primary nonlymphoproliferative tumors of the spine are uncommon and make up fewer than 5% of bone neoplasms; the annual incidence of primary spine tumors is in the range of 2.5-8.5 per 100,000 population. Metastatic disease of the spine is much more common. Approximately 40-80% of patients who die of cancer have bony metastases at the time of death, with the spine being the most common metastatic skeletal location.
Neoplastic disease, however, can present with back pain that is indistinguishable from back pain resulting from more benign causes. Therefore, the physician caring for patients complaining of back pain is faced with the challenges of (1) distinguishing benign causes from those that can be neurologically or systemically devastating and (2) prescribing the appropriate treatment.
This distinction sometimes can be difficult to make because of the complicated architecture of the spine (see Anatomy). The physician must consider differential diagnoses of degenerative processes, infections, muscular strains, neurologic impingements, and, finally, neoplastic processes. With thorough history taking, physical examination, and diagnostic imaging, the physician can acquire enough information to make the correct diagnosis in an efficient manner.
Anatomy
The spine consists of 33 vertebrae that form the bony spinal column. The spinal column can be divided into the cervical, thoracic, lumbar, and sacrococcygeal regions. Although morphologically distinct, each vertebra in the subaxial cervical, thoracic, and lumbar spine has a complex architecture, consisting of a vertebral body, pedicles, laminae, and spinous and transverse processes.
The bony canal provides protection and support to the fragile spinal cord and nerve roots within the dural sac. The soft tissues surrounding the bony spine vary by location from the thick dorsal paraspinous musculature to the vital organs and vessels within the mediastinal, thoracic, peritoneal, and retroperitoneal spaces.
Prognosis
Chang et al conducted a study to evaluate local control rate and to identify prognostic factors after stereotactic radiosurgery for treatment of primary malignant spinal tumors. [3] Median age of the 29 patients was 46 years (range, 11-68). Histologic diagnoses included chordoma (n = 1), chondrosarcoma (n = 5), osteosarcoma (n = 3), synovial sarcoma (n = 3), plasmacytoma (n = 2), Ewing sarcoma (n = 2), malignant peripheral nerve sheath tumor (n = 2), and malignant fibrous histiocytoma (n = 1). Mean follow-up was 50 months (range, 8-126).
Surgical resection was the initial treatment in 25 cases, percutaneous biopsy in four. [3] Stereotactic radiosurgery was used as primary treatment in 14 cases and as salvage treatment for progressive lesions in 15. Eleven patients had undergone previous conventional external-beam radiation therapy before stereotactic radiosurgery. Median tumor volume was 14 cm3 (range, 2.0-235). Delivered radiation doses were 12-50 Gy in two to six sessions. The mean radiation dose converted into a biologic effective dose (BED) was 60 Gy (range, 43-105).
Mean overall survival was 84 months for chordoma patients and 104 months for sarcoma patients. [3] The investigators found no factors that affected overall survival. The mean local progression-free survival was 56 months for chordoma patients and 73 months for sarcoma patients. The recurrent mode of presentation was predictive of local progression of spinal sarcomas. For patients with chordoma, no factors were found to correlate with local recurrence.
Kose et al conducted a study of the effect of early rehabilitation on neurofunctional outcome after surgery in children with spinal tumors. [4] The investigators reviewed medical charts and radiographic records of 70 pediatric patients (aged 1-17 years) who underwent surgery for the removal of spinal tumor. The patients received rehabilitation treatment beginning 4 days (range, 2-7 days) after surgery for 10 days (range, 7-23 days).
Results were assessed on the basis of scoring on the Modified McCormick Scale, the Functional Independence Measure for Children, the American Spinal Injury Association Impairment Scale, and the Karnofsky Performance Status Scale. [4] Sensory function, motor function, and activity of daily living were significantly improved for the patients who received early rehabilitation. Tumor setting, the level of localization, and the patients' clinical symptoms had no bearing on neurofunctional outcomes.
-
Spinal tumors. Chordoma histology.
-
Spinal tumors. Higher magnification of chordoma histology demonstrates characteristic physaliferous cells.
-
Spinal tumors. Aneurysmal bone cyst histology.
-
Spinal tumors. Coned-down view of lateral thoracic spine in patient with chondrosarcoma.
-
Spinal tumors. Axial CT scan at level of chondrosarcoma seen on previous x-ray image.
-
Spinal tumors. T2-weighted MRI scan of chondrosarcoma in same patient.
-
Spinal tumors. Photograph of patient's back at time of surgery, exhibiting course of definitive incision to excise chondrosarcoma en bloc with previous biopsy tract included with resection.
-
Spinal tumors. Histology of chondrosarcoma at 40 times magnification.
-
Spinal tumors. Lateral cervical spine x-ray demonstrating osteoblastoma in posterior elements of C3 and C4.
-
Spinal tumors. MRI of osteoblastoma in posterior elements of C3 and C4 seen on previous x-ray image.
-
Spinal tumors. Histology of osteoblastoma at low magnification.
-
Spinal tumors. Higher magnification of osteoblastoma.
-
Spinal tumors. Coned-down view of hemangioma in thoracic spine.
-
Spinal tumors. Axial CT scan of hemangioma in lumbar vertebra.
-
Spinal tumors. Axial CT scan of thoracic vertebra, which demonstrates nidus of osteoid osteoma in posterior elements.
