In the past, primary tumors of the cervical spine were discovered only by standard radiographs when associated with significant bone loss. Today, although plain radiographs remain the first imaging study, bone scan, CT, and MRI help to make definitive identification in patients suspected of having a malignant process (3). Symptoms that should suggest performing further studies after a negative plain radiograph are dysphagia, persistent night pain, sudden occurrence of neurologic symptoms, and extremity pain, which may or may not fit a dermatomal distribution.

Due to the superposition of anatomical profiles typical of the standard radiographic picture of the cervical spine, the plain radiograph may be normal in some smaller lesions and in some myxoid tumors with expansion outside the vertebral body without evidence of bone involvement. Specific tumors have a more typical appearance; for example, chondrosarcomas are frequently calcified and lobulated (Fig. 57.2 and 57.2), and plasmacytomas and chordomas appear mostly as pure radiolucent lesions with variable definitions of their margins and are often difficult to distinguish from one another on plain radiographs. High-grade malignancy, such as an osteosarcoma, typically presents as an aggressive,
osteolytic destructive process accompanied by variable amounts of ossification. Round cell tumors (i.e., Ewing’s sarcoma and lymphomas) present with a typical permeative pattern and an associated soft tissue mass before there is evidence of bone destruction. The disks are involved only rarely but sometimes are surrounded by tumor. This factor is important in distinguishing tumors from pyogenic and tuberculous spinal infections.

The technetium-99 (⁹⁹Tc) scan in the workup of a malignant tumor is rarely necessary to find the lesion, which is almost always evident on standard radiographs. More frequently, the bone scan is used for detection of possible distant metastases. Only in cases of tumors like chordoma, which are difficult to see on plain radiographs due to the

infiltrative pattern of growth, are isotope scans helpful in guiding the use of a CT scan or MRI. Plasmacytomas are not always detectable by bone scan. Tomographic bone scan technology, however, can improve the sensitivity but not necessarily the specificity.

The CT scan is highly sensitive for early bone destruction and in some clinicians’ minds remains unique for planning definitive surgical treatment. Contrast enhancement is often requisite to the careful evaluation of tumor margins and the tumor’s intrinsic vascularity. Preoperative CT imaging also provides an assessment of bony involvement and is important in the planning of both surgical resection and instrumented fixation.

The MRI has greater sensitivity than the bone scan in detecting occult lesions not visualized on standard radiographs. The advantages are particularly evident for plasmacytomas. Furthermore, it is usually well tolerated, noninvasive, and safe. Compared with normal bone marrow, most tumors demonstrate decreased signal intensity on T1-weighted images and increased signal on T2-weighted sequences. Also, MRI is extremely sensitive to alterations in the vertebral body marrow, but it lacks specificity as to the etiology of the various pathologic processes. Any disorder or therapeutic procedure resulting in loss of myeloid elements—such as radiation therapy—may demonstrate increased signal intensity in the marrow secondary to fatty replacement of hematopoietic tissue. Soft tissue extension of a tumor and its particular relationship with the dura and nerve roots are better visualized by MRI than by CT scan (3).

In most countries, myelography has now been replaced by MRI to assess spinal cord or nerve root compression, but still can be useful in concert with CT when a stainless steel device, which is known to cause metal artifacts, is present. CT myelography is also important in the diagnosis of spinal cord compression in patients who have a medical contraindication to MR imaging.

Angiography allows visualization of the vascularity of the tumor and the relationships of the tumor mass to the vertebral arteries. Preoperative embolization can be helpful in reducing intraoperative bleeding when an intralesional procedure is planned, but it can be performed only rarely because of common vascularity with the cervical cord and should be performed only in experienced institutions (14).

Histologic confirmation of the diagnosis is mandatory to distinguish between primary and secondary malignancies and to differentiate malignancies that require varied treatments (e.g., chordoma vs. plasmacytoma) (1,5,15). Trocar/needle biopsy under CT scan guidance (Fig. 57.3) is theoretically a good way to achieve a diagnosis and usually does not require general anesthesia. Often CT scanning will help in reaching even the smallest of lesions. Correct use of this technique minimizes tumor contamination (16). The trocar/needle should be introduced at a point within the incision line, and the direction should pass through a muscle in order to resect the entire scar and needle track together with the tumor and ensure en bloc resection. Pressure should also be applied to reduce bleeding as the trocar is removed. In the cervical spine, this procedure is technically demanding and frequently is not well tolerated by patients. Knowing that these malignant primary tumors of the cervical spine are often extracompartmental at the time of discovery, it is generally not feasible to perform an en bloc resection. However, perioperative frozen sections should be examined before submitting the patient to an intralesional excision. The extent of surgical extirpation, together with the necessity of adjuvant therapies, will be decided by this important information obtained for histologic diagnosis. In rare cases of resectable tumors (small and often dorsally located), particular attention should be given to the imaging studies. In fact, the peculiar pattern of chondrosarcoma or chordoma must make the surgeon vigilant. In these cases, the risk of contamination by the myxoid tissue is extremely high, and at times justifies performing primary en bloc resection without previous histologic confirmation (Fig. 57.2).