Several problems arise in the diagnosis of spinal cord tumors in addition to several previously mentioned. In the early stages, neoplastic compression or invasion of the cord must be distinguished from other diseases that cause pain over certain segments of the body, for example, diseases affecting the gallbladder, pancreas, kidney, stomach and intestinal tract, and pleura. Localization of the pain to a dermatome; its intensification by sneezing, coughing, and straining, and sometimes by recumbency; and the finding of segmental sensory changes and minor alterations of motor, reflex, or sensory function in the legs will usually provide the clues to the presence of a spinal cord–radicular lesion. MRI will settle the diagnosis in most instances. The pain of tumor or blood clot in the retroperitoneal space may cause an orthostatic and nocturnal back pain that is similar to that of spinal tumor.
There is then the problem of locating the segmental level of the lesion. At first, the sensory and motor deficits may be most pronounced in those parts of the body farthest removed from the lesion, that is, in the feet or lumbosacral segments. Later the levels of the sensory and motor deficits ascend, but they may still be at a level several segments below the lesion. In determining the level of the lesion, the location of back pain, root pain, and atrophic paralysis are of greater help than the upper level of hypoalgesia.
Once vertebral and segmental levels of the lesion are settled, there remains the necessity of determining whether the lesion is extradural, intradural–extramedullary, or intramedullary and whether it is neoplastic. If there is a visible or palpable spinal deformity or radiographic evidence of vertebral destruction, one may confidently assume an extradural localization. Even without these changes, one still suspects an extradural lesion if root pain developed early and is bilateral, if pain and aching in the spine are prominent and percussion tenderness is marked, if motor symptoms below the lesion preceded sensory ones, and if sphincter disturbances were late. However, to distinguish between intradural–extramedullary lesions and intramedullary lesions on clinical grounds alone is often difficult. The findings of segmental amyotrophy and sensory loss of dissociated type (loss of pain and temperature and preservation of tactile sensation) point to an intramedullary lesion.