Extradural tumors, both primary and secondary, must be differentiated from cervical spondylosis, tuberculous granuloma, sarcoidosis, arteriovenous malformations of the cord, spinal dural fistulas, and certain chronic pyogenic or fungal granulomatous lesions, as well as from lipomas in patients receiving corticosteroids for prolonged periods and from the necrotizing myelopathy associated with occult tumors or occurring independently of them. A number of rarer conditions of the vertebral bodies such as bone cysts, chondromas, eosinophilic granuloma, chordomas, and giant cell tumors must also be considered; these are summarized by Ropper and coworkers (2011). In the thoracic region, a ruptured disc or eventration of the cord through a dural tear is always a possibility. In the region of the lower back, that is, over the cauda equina, one must also distinguish between tumor and protruded inter-vertebral disc. Here, an extradural tumor may produce mainly sciatic and low back pain with little or no motor, sensory, reflex, or sphincteric disturbances. With intradural–extramedullary lesions, the important diagnostic considerations are meningioma, neurofibroma, meningeal carcinomatosis, cholesteatoma, and teratomatous cyst, a meningomyelitic process, or adhesive arachnoiditis. Intramedullary lesions are usually gliomas, ependymomas, or vascular malformations or, in the context of a known carcinoma, intramedullary metastases. The definition of vascular malformations by means of selective spinal angiography was discussed in an earlier section. Normal protein in the CSF and negative MRI effectively exclude an intramedullary tumor.
The main consideration in the management of epidural metastases is the need for early diagnosis, at a stage when only back pain is present and before neurologic symptoms and signs have appeared. Once these signs appear, especially sphincter disturbances, the results of treatment are less successful but may still result in good limb and bladder function. Epidural growths of carcinoma and lymphoma have been typically managed by administration of high to moderate doses of corticosteroids and radiation of the region of tumor although surgical options exist and provide faster decompression and the opportunity for stabilization of the spinal column. The choice of surgery or stereotactic radiation is complex, partly stylistic, and dependent on the likelihood of survival as noted below, and possibly by the radiosensitivity of the tumor and as summarized by Ropper and Ropper. Either treatment may be supplemented by endocrine therapy (for carcinoma of breast and prostate), and of antineoplastic drugs (for certain lymphomas and myelomas. Pain relief is sometimes difficult to attain and requires narcotics. Gilbert and associates presented evidence that patients who receive high-dose corticosteroids (16 to 60 mg of dexamethasone) and fractionated radiation (500 cGy on each of the first 3 days and then spaced radiation up to 3,000 cGy) do as well as those who have surgical decompression. However, a comparison of five different radiation programs by Nieder and colleagues suggested there is little difference between them. An often cited review of the radiotherapy options was given by Gerszten and colleagues in 2009 but the techniques change so rapidly that it is difficult to determine and compare outcomes. The issue of radiosensitivity of any particular tumor has become a relative one as high doses of focal radiation are being delivered in one or a few fractions by special (stereotactic) techniques.