Intramedullary Spinal Tumor

Intramedullary Spinal Tumor

Summarize

Intramedullary spinal cord tumors (IMSCT) are very rare, accounting for only 4 to 6 percent of all central nervous system tumors. Most intramedullary spinal cord tumors are benign or low-grade (WHO-defined grade I and II tumors). Intramedullary spinal cord tumors rarely metastasize.

 

 

 

Intramedullary spinal cord tumors can occur anywhere in the spinal cord, but are most commonly located in the cervical and thoracic spinal cord and are less common in the lumbar spinal cord. The incidence is roughly equal in boys and girls.

 

 

 

In terms of histology, most intramedullary spinal cord tumors in children are astrocytoma and ependymoma. Other less common pathological types include hemangioblastoma, neuroglial tumor, oligodendroglioma, subependymoma, neuroblastoma, etc.

 

 

 

The initial symptoms of intramedullary tumors in children are often not obvious, leading to delayed diagnosis. For months or even years before the disease is diagnosed, patients may experience mild symptoms and signs, such as pain, weakness, sensory abnormalities, spinal deformities, sphincter dysfunction (such as urinary and fecal incontinence), or cervical spinal cord symptoms. Sometimes, there may also be a gradual decline in neurological function.

 

 

 

Given the rarity of intramedullary spinal cord tumors, their diagnosis and treatment often rely on the diagnostic and therapeutic approaches used for other central nervous system tumors. If the lesion can be surgically removed, surgery is the primary treatment for primary intramedullary spinal cord tumors. However, surgery may also result in severe neurological deficits in children. The comprehensive treatment of such tumors requires a multidisciplinary team, including pediatric neurosurgeons, neuro-oncologists, pediatric neurologists, and nursing experts, to develop a treatment plan.

Epidemiological

In the United States, there are about 100 to 200 new cases of IMSCT per year, an incidence rate of less than one in 100,000 people.

Etiology & Risk Factors

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Classification & Staging

Spinal cord tumors are generally divided into three categories:

 

 

 

(1) Epidural: the most common spinal cord tumor, but usually metastatic;

 

 

 

(2) Intradural and extramedullary: accounting for 70%~80% of all primary spinal cord tumors;

 

 

 

(3) Intradural and intramedullary: accounting for 20%~30% of all primary intradural tumors.

 

 

 

Gliomas account for 80% of all intramedullary tumors. Gliomas can be further categorized into astrocytomas (60% to 70%) and ependymomas (30% to 40%). Astrocytomas are more common in children than in adults, while ependymomas are more prevalent in adults. Hemangioblastomas are the third most common type of intramedullary spinal cord tumor, accounting for 2% to 15% of all intramedullary tumors. Metastatic intramedullary tumors are relatively rare; if they occur, they are usually metastases from lung or breast cancer, making up about 2% of all intramedullary tumors. However, autopsy reports indicate that 0.9% to 2.1% of all cancer patients exhibit intramedullary spinal cord metastasis. Therefore, the incidence of these tumors may be higher than initially estimated.

 

 

 

50.  astrocytoma

 

 

Astrocytomas, the most common type of intramedullary spinal cord tumors, are characterized by an unclear interface between the tumor and the spinal cord. These tumors can form cavities within the spinal cord and may evolve into highly malignant subtypes. Astrocytomas are most commonly found in the thoracic spinal cord and may be associated with neurofibromatosis, a condition that affects multiple parts of the body. They are more prevalent in males. In adults, these tumors are typically high-grade, but the grade tends to decrease with age. Approximately 25% of adult astrocytomas may become malignant.

 

 

 

50.  ependymocytoma

 

 

Ependymomas in intramedullary spinal cord tumors can arise from the intracranial ventricular system or within the spinal cord. Tumors originating from the spinal cord may also result from the dissemination of tumor cells from the intracranial cerebrospinal fluid. Ependymomas are more common in the cervical spinal cord region of children and have a lower incidence than astrocytomas.

 

 

 

A foreign study found that of 117 children with intramedullary spinal cord tumors, only 19 were ependymomas, or 16 percent of the total. The proportion of ependymomas increases with age.

 

 

 

Ependymoma (classified as Grade II by the World Health Organization WHO) has been found to potentially contain DNA fragments of the SV40 virus. This discovery has sparked widespread concern, given the widespread use of polio vaccines contaminated with the SV40 virus between 1955 and 1962. However, these findings have not been confirmed by other researchers, and the role of SV40 in the pathogenesis of ependymoma remains unclear.

 

 

 

In addition, intramedullary spinal cord tumors are associated with genetic factors. Testing for various gene mutations could help understand clinical manifestations and develop new therapies to treat these tumors.

 

 

 

Other clinical syndromes associated with intramedullary spinal cord tumors include neurofibromatosis type 1 and 2 (NF-1, NF-2) and Von Hippel-Lindau disease (VHL).

Clinical Manifestations

Spinal cord intramedullary tumors can have a variety of symptoms depending on the severity and stage of the disease, as well as the growth rate, location, and longitudinal length of the tumor.

 

 

 

In general, if the child has bilateral motor and sensory impairment, sensory symptoms do not involve the head and face and are often accompanied by other upper motor neuron symptoms (such as convulsions, paralysis, etc.), spinal cord lesions should be suspected.

 

 

 

Back or neck pain is the most common manifestation of intramedullary spinal cord tumors. The pain may be caused by dural expansion and irritation. The pain is continuous, and each child's sensation will vary. Usually, the pain becomes more severe when lying on the back.

 

 

 

If symptoms such as weakness, spasms, and clumsiness occur, it suggests that the tumor may be compressing the nerve roots. If the tumor extends into the skull, surrounding cranial nerves may be compressed, leading to sensory abnormalities or numbness in the affected area. For example, a lateral tumor can compress the hypoglossal nerve, causing paralysis and atrophy of the tongue on the same side. Tumors around the upper cervical spinal cord can also compress the accessory nerve, resulting in weakness and atrophy of the sternocleidomastoid and trapezius muscles (for example, difficulty turning the head to one side, drooping shoulders, and weak shoulder lifting). The condition may start on one side and progress from the distal end of the nerve to the other side. Additionally, nerve root lesions are also associated with involvement of the lumbosacral region. The incidence of hydrocephalus in intramedullary spinal cord tumors is approximately 1-8%. Hydrocephalus can be caused by subarachnoid hemorrhage or tumor obstruction.

 

 

 

Other clinical manifestations include upper motor neuron paralysis, temperature sensation disorders, proprioceptive disorders, and gait abnormalities. When the tumor affects the autonomic nervous system, it can cause dysfunction of the sympathetic and parasympathetic nervous systems, leading to symptoms such as palpitations, shortness of breath, indigestion, loss of appetite, headaches, dizziness, low-grade fever, chills, hypertension, hypotension, vomiting, constipation, diarrhea, insomnia, tinnitus, back pain, vertigo, muscle twitching, and a feeling of chest pressure.

Clinical Department

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Examination & Diagnosis

Accurate diagnosis of intramedullary spinal cord tumors is crucial for providing the best treatment and achieving optimal outcomes. Magnetic resonance imaging (MRI) scans are the preferred method for diagnosing these tumors. Ependymomas are typically located in the central part of the spinal cord, showing symmetrical expansion and diffuse heterogeneous enhancement. In contrast, astrocytomas tend to be eccentrically located and may exhibit extrinsic components, which can be non-enhancing or show uneven enhancement, or have enhancing nodules. MRI can also help identify the spinal cord-tumor interface, detect associated cysts or syringomyelia, and provide valuable information for further surgical treatment.

 

 

 

The most common intramedullary spinal cord tumors are astrocytomas, ependymomas, and hemangioblastomas, followed by other rare types. Each specific type has its own characteristics. Due to their rarity, these tumors are often difficult to detect and frequently misdiagnosed, leading to delayed treatment for patients. Despite their distinctive pathological features, these tumors remain challenging to differentiate clearly in radiology and clinical diagnosis. Preoperative neurological function and tumor histology are the two most critical factors affecting the outcomes of treatment for these lesions. A deep understanding of these tumors is essential for early diagnosis.

Clinical Management

The main treatment methods for intramedullary tumors in children are surgery, radiotherapy and radiotherapy combined with chemotherapy.

 

 

 

1. Surgery

 

 

Surgical resection is the preferred treatment for intramedullary spinal cord tumors in children.

 

 

 

The extent of resection depends on the type of tumor, as some tumors such as ependymoma, ganglioneuroma and hairy cell astrocytoma have clearer boundaries and a lower recurrence rate after radical resection.

 

 

 

Other types, such as high-grade astrocytomas, have a higher recurrence rate because the spinal cord-tumor boundary is not clear and it is difficult to completely remove them.

 

 

 

2. Radiotherapy

 

 

Many reports suggest that radiotherapy is effective for malignant spinal cord tumors, but its use in pediatric patients remains controversial because of the potential for local recurrence, radiation myelopathy, spinal deformity, or secondary tumor development.

 

 

 

In brain tumors, postoperative radiotherapy can prevent low-grade tumors from becoming high-grade tumors, but this is not the case for spinal cord tumors. Low-grade intramedullary spinal cord tumors have little chance of becoming high-grade tumors without radiotherapy.

 

 

 

Therefore, radiotherapy can be used to treat patients with low-grade malignancies that are not completely resected, especially in cases where surgery is not possible for some reason or for tumors with a high likelihood of rapid recurrence or high-grade astrocytomas.

 

 

 

Radiotherapy may not be used in cases of complete or near complete resection of ependymomas and low-grade astrocytomas.

 

 

 

3. Radiotherapy combined with chemotherapy

 

 

Because children are more sensitive to the harmful effects of radiation, chemotherapy plays an important role in the treatment of intramedullary spinal cord tumors in children. Chemotherapy is usually used in combination with radiotherapy to treat malignant intramedullary tumors, but the effectiveness of this approach is somewhat uncertain.

 

 

 

According to reports, children with low-grade astrocytomas respond differently to chemotherapy regimens. The French Pediatric Oncology Society conducted a study using various chemotherapy drugs, including carboplatin, procarbazine, vincristine, cyclophosphamide, etoposide, and cisplatin, to treat intramedullary gliomas in the spinal cord. Most patients experienced good progression-free survival, and their neurological function significantly improved.

 

 

 

4. Other new treatment options

 

 

In order to better help patients with intramedullary spinal cord tumors, medical scientists are actively researching new treatment options, including targeted, local drug delivery and nanomedicine technologies, among others. These and other future research will bring more promising new therapies for these malignant diseases.

Prognosis

Doctors can judge the future of children with intramedullary spinal cord tumors after surgery through two important factors:

 

 

 

Pathological histological grading of tumors;

Neurological status before surgery.

 

 

 

Follow-up & Review

Children with significant preoperative neurological deficits are more likely to experience postoperative deterioration. Children with ependymoma (WHO Grade II) have a better prognosis than those with astrocytoma (WHO Grade II). Patients with glioblastoma multiforme (WHO Grade I) have a better prognosis than those with ependymoma.

 

 

 

Furthermore, the patient's prognosis also depends on the extent of surgical resection and whether the tumor is primarily solid or mainly cystic. About 30% of patients with nearly total resection (removing about 80% of the tumor) may experience a recurrence within five years after surgery. The less the tumor is removed, the higher the recurrence rate. Therefore, regular follow-up is essential.

 

 

 

Benign intramedullary spinal cord tumors should be monitored annually. Since most intramedullary spinal cord tumors in children are benign, annual follow-ups are usually sufficient. Additionally, family members should closely monitor any signs of tumor progression to seek medical attention promptly if a recurrence is suspected. For children diagnosed with malignant tumors, more frequent follow-ups are necessary.

Daily Care

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Cutting-edge therapeutic and clinical Trials

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References

        References:

 

                1. https://www.neurosurgery.theclinics.com/article/S1042-3680(05)00061-6/abstract

                2. http://thejns.org/doi/pdfplus/10.3171/2015.5.FOCUS15158

                3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4611888/

                4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3208914/

                5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4577312/

                6. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4771497/

                7. https://www.ncbi.nlm.nih.gov/books/NBK442031/

Audit specialists

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