| disease | Spinal Cord Tumor |
Spinal cord tumors are one of the major causes of compression of the spinal cord and cauda equina, and must be differentiated from those caused by degenerative spinal diseases. The term "spinal cord tumors" in this section is used in a broad sense, also encompassing tumors arising from the spinal canal and adjacent tissues of the spinal cord.
bubble_chart Epidemiology
Incidence: Primary spinal tumors occur in 2.5 people per 100,000 population annually. The incidence is similar between genders, although spinal meningiomas are more common in women, while ependymomas are more frequently seen in men. The thoracic spinal cord has a higher incidence rate, but when calculated proportionally by segment length, the incidence is roughly equal.
bubble_chart Clinical Manifestations
Symptoms: The symptoms of spinal cord and nerve root compression caused by spinal cord tumors are similar to those caused by degenerative spinal diseases.
(1) Intramedullary tumors: Intramedullary tumors mainly include astrocytomas and ependymomas, accounting for about 20% of all spinal cord tumors. Intramedullary tumors often involve multiple segments of the spinal cord. Involvement of the dorsal root entry zone may cause radicular pain, but this is uncommon. Muscle atrophy and fasciculations are often observed, while pyramidal tract signs appear later and are usually not prominent. Sphincter dysfunction may occur early, while Brown-Séquard syndrome is rare. Cerebrospinal fluid changes are often not significant, and the Queckenstedt test usually does not show obstruction.
(2) Extramedullary tumors: These include intradural and extradural tumors. The former commonly include neurinomas (including neurofibromas) and meningiomas, accounting for about 55% of all spinal cord tumors, while the latter account for 25%. Extramedullary tumors generally involve fewer spinal segments. Muscle atrophy is rare, but tumors in the cauda equina at an advanced stage may cause significant lower limb muscle atrophy. Sphincter dysfunction usually appears at an advanced stage. Incomplete Brown-Séquard syndrome is common, and cerebrospinal fluid changes appear earlier. The Queckenstedt test often shows obstruction, and the more complete the obstruction, the more significant the increase in protein.
Neurological localization signs: This refers to longitudinal localization, i.e., the neurological signs of lesions at different segments.(1) Craniocervical junction: Tumors in this region may involve the 11th and 12th cranial nerves and compress the posterior columns, causing disturbances in position sense, vibration sense, and light touch. The limbs exhibit upper motor neuron damage, and sensory disturbances may occur in the C2 dermatome.
(2) Cervical spinal cord region: Lesions in the upper cervical spinal cord may cause occipital and cervical pain and paresthesia. Spastic quadriplegia may occur below the lesion level, with hyperactive biceps reflexes. A C5 spinal cord lesion may lead to atrophy and paralysis of the deltoid, biceps, and supinator muscles, with sensory disturbances extending to the lateral arm and loss of biceps and supinator reflexes. A C6 lesion causes triceps and wrist extensor paralysis, partial wrist drop, and sensory disturbances in the corresponding dermatomes. A C7 lesion results in wrist flexor and finger flexor/extensor paralysis, with sensory disturbances involving the ulnar side of the midline of the arm. A C8 lesion causes intrinsic hand muscle atrophy and paralysis, claw hand deformity, and may present with Horner's sign. Sensory disturbances affect the medial arm and the 4th and 5th fingers.
(3) Thoracic spinal cord region: Clinical localization usually relies on the level of sensory disturbance, as it is difficult to judge based on intercostal muscle strength. Lower abdominal muscle paralysis with normal upper abdominal muscles may lead to Beevor's sign, where the umbilicus moves upward when the patient, lying supine, attempts to sit up against resistance applied to the chest. The lower abdominal reflex is absent.
(5) Conus medullaris and cauda equina region: Early symptoms may include lumbago, pain or numbness in the saddle area and lower limbs, often misdiagnosed as sciatica. Sphincter dysfunction appears early. Flaccid paralysis of the lower limbs, muscle atrophy, and foot drop may occur. Sensory loss may affect the lumbosacral dermatomes, especially the saddle area, and occasionally lumbosacral, buttock, hip, or heel ulcers may develop.
bubble_chart Auxiliary Examination
X-ray examination: Some spinal cord tumors may show the following abnormalities on plain X-ray films.
1. Destruction of vertebral bone, with partial vertebral body or pedicle showing translucent changes, and vertebral collapse.
2. Changes in the contour and distance of the pedicles, enlargement of the intervertebral foramen, and localized expansion of the spinal canal.
3. Deformation of paravertebral tissues, with the tumor originating from paravertebral tissues or extending through the intervertebral foramen.
4. Bone proliferation may be observed in fleshy tumors, bone hemangiomas, and meningiomas.
CT and CTM: Neurological examination should accurately indicate the lesion site for CT examination. Both intramedullary and extramedullary tumors can be clearly visualized, and vertebral destruction is easily identified.
MRI: Most spinal cord tumors, including metastatic tumors, show decreased or unchanged signal intensity on T1-weighted images. On T2-weighted images, the signal intensity is enhanced, but osteoblastomas and some prostate or pancreatic cancer bone metastases exhibit decreased signal intensity.
bubble_chart Treatment Measures
The only effective treatment for neurological dysfunction caused by spinal cord tumors is surgical resection. When neurological symptoms are severe or rapidly progressing, surgery should be performed as an emergency. For extramedullary intradural tumors such as meningiomas and schwannomas, removal relieves spinal cord compression with good outcomes, sometimes even allowing complete recovery from severe spastic paralysis that has persisted for years. In contrast, intramedullary tumors like astrocytomas and ependymomas, which have indistinct boundaries with normal spinal cord tissue, are difficult to remove completely and accurately, resulting in poorer outcomes. Extradural metastatic tumors often invade the spinal cord, compromising its blood supply, making decompression less effective or unable to alleviate symptoms. In recent years, advancements in microsurgical instruments, surgical techniques, the refinement of operating microscopes, the application of lasers, and the use of SEP for monitoring have improved surgical success rates and reduced disability rates.
Spinal cord tumors need to be differentiated from other spinal cord disorders, such as adhesive arachnoiditis, multiple sclerosis, amyotrophic lateral sclerosis, and syringomyelia. Orthopedic diseases that require differentiation include spinal subcutaneous nodules and degenerative spinal diseases.
1. Spinal structural diseases often present with chronic toxic symptoms such as low-grade fever and night sweats. The lesions frequently erode the intervertebral discs and corresponding vertebral margins, and paravertebral cold abscesses aid in differential diagnosis.
2. Degenerative spinal diseases cause intervertebral discs and ligaments to protrude into the spinal canal, leading to compression of the spinal cord and nerves. Imaging signs of spinal degeneration are almost universally present after middle age, and the differential diagnosis from spinal cord tumors relies on careful neurological evaluation supplemented by imaging studies.
