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SPINAL CORD (INTRAMEDULLARY) TUMORS
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Astrocytoma and ependymoma account for approximately 90% of spinal cord tumors (Table 24-1). Other tumors of the cord are rare. The presenting symptoms of spinal cord tumors are often nonspecific, and substantial delay in diagnosis is common. Typical early features are back pain, weakness, and clumsiness. Some patients develop torticollis or progressive scoliosis. Lumbar tumors can lead to bowel and bladder sphincter dysfunction. Clinical examination often demonstrates pathological reflexes and/or sensory change. MRI is the imaging technique of choice for the detection of these lesions.1–9
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Astrocytoma is the most common spinal cord tumor in children, accounting for approximately 60% of intramedullary neoplasms. This lesion results from the neoplastic transformation of astrocytes. Astrocytoma can arise in children of any age, including infants. The mean age at presentation in the pediatric age group is 6 to 7 years. There is no substantial gender predilection. The cervical and thoracic regions are the most common sites, although any portion of the cord can be involved. About half of spinal cord astrocytomas in children involve the entire cord, that is, holocord astrocytoma. Holocord astrocytoma is most common during the first year of life. Spinal astrocytoma can occur following radiation therapy; radiation-induced astrocytomas tend to be high-grade malignancies.10–12
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The clinical manifestations of spinal cord astrocytoma are variable. Potential findings include pain, gait disturbance (thoracic tumor), torticollis (cervical tumor), scoliosis, paralysis, hyporeflexia, sensory deficits, and sphincter dysfunction (lumbar tumor). There are 2 distinct clinical syndromes associated with holocord astrocytoma. (1) A lesion that is solid in the cervical region and cystic in the caudal portion of the cord most often results in unilateral upper extremity weakness, mild spastic weakness of the lower extremities, and (sometimes) neck pain. (2) When the major solid portion of the tumor is located in the thoracic or lumbar region, the major clinical finding is progressive spastic paraplegia, sometimes accompanied by thoracic pain and scoliosis. If the solid portion extends into the conus medullaris, lower extremity deep tendon reflexes are diminished and sphincter dysfunction is common.
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Astrocytomas range from well differentiated to anaplastic types (grades I to IV). The aggressive malignant forms are more common in children than in adults. Malignant astrocytoma and glioblastoma account for up to one-quarter of astroglial spinal cord tumors in children. Astrocytomas are often infiltrative and are difficult or impossible to completely resect. The neoplasm causes diffuse enlargement of the involved portion of the cord; spread predominantly occurs in a longitudinal fashion. About two-thirds of spinal astrocytomas are predominantly solid; macroscopic ...