Intramedullary syringomyelic syndrome No single symptom is unique to the intramedullary tumors. Some degree of pain, sometimes minor, is common and is almost invariably present with tumors of the filum terminale. Ependymomas and astrocytomas, the two most common intramedullary tumors, usually give rise to a mixed sensorimotor tract syndrome. When the intramedullary tumor involves the central gray matter, a central cord, or syringomyelic syndrome may result. The main features are segmental or dissociated sensory loss, amyotrophy, early incontinence, and late corticospinal weakness. Sacral sparing of sensation may be found as described in Chap. 8 on the sensory syndromes but is of less value in distinguishing intramedullary from extramedullary lesions. A dissociation of thermal pain and tactile sensory loss over several contiguous segments on the trunk is a more dependable sign of an intramedullary lesion. Rarely, an extramedullary tumor may give rise to a syringomyelic sensory syndrome, possibly by causing vascular insufficiency in the central portion of the cord.
Special spinal syndromes Unusual clinical syndromes may be found in patients with tumors in the region of the foramen magnum, as discussed in Chap. 3. They produce quadriparesis with pain in the back of the head and stiff neck, weakness and atrophy of the hands and dorsal neck muscles, marked imbalance, and variable sensory changes or, if they spread intracranially, there may be signs of cerebellar and lower cranial nerve involvement. Slowly growing tumors in this region, such as meningiomas, characteristically produce an “around the clock” progression of weakness beginning in one limb and proceeding to the adjacent one in a clockwise or counterclockwise direction. Lesions at the level of the lowermost thoracic and the first lumbar vertebrae may result in mixed cauda equina and spinal cord symptoms. A Babinski sign indicates that the spinal cord is involved above the fifth lumbar segment.
Lesions of the cauda equina alone, always difficult to separate from those of the lumbosacral plexuses and multiple nerves, are usually attended in the early stages by sciatic and other root pain and lumbar ache, which are variously combined with a bilaterally asymmetrical, atrophic, areflexic paralysis, radicular sensory loss, and sphincteric disorder. These must be distinguished from lesions of the conus medullaris (lower sacral segments of the spinal cord), in which there are early disturbances of the bladder and bowel (urinary retention and constipation), back pain, symmetrical hypesthesia or anesthesia over the sacral dermatomes, a lax anal sphincter with loss of anal and bulbocavernosus reflexes, impotence, and sometimes weakness of leg muscles. Sensory abnormalities may precede motor and reflex changes by many months. Very rarely, for unclear reasons, tumors of the thoracolumbar cord (intramedullary, as a rule) are associated with markedly elevated spinal fluid protein and hydrocephalus; these respond to shunting and removal of the spinal tumor (Feldman et al). Less often, these tumors are associated with a pseudotumor cerebri syndrome.