Spinal Ependymoma
Spinal ependymoma originates from the ependymal cells of the central canal or the filum terminale of the spinal cord, accounting for approximately 60% of primary intramedullary tumors. The peak incidence occurs in individuals aged 30 to 40 years. About 8% to 10% of ependymomas with MYCN gene amplification are characterized by aggressive behavior and are prone to disseminating and metastasizing in the central nervous system.
Spinal ependymomas typically exhibit slow growth. At the onset, symptoms are often mild, with the most common being unilateral or bilateral limb pain and numbness. In some cases, tumor hemorrhage may lead to acute symptom exacerbation. MRI findings often show the tumor located centrally within the spinal cord, expanding uniformly outward and progressively occupying the full width of the spinal cord. Syringomyelia may develop at one or both ends of the tumor. After contrast injection, the solid portion of the tumor often shows heterogeneous but relatively uniform enhancement, with well-defined boundaries. Surgical resection is the preferred and primary treatment for spinal ependymoma. Compared with intracranial ependymomas, spinal ependymomas generally have a favorable prognosis.
Spinal Astrocytoma
Spinal astrocytoma ranks second in incidence among intramedullary spinal tumors, following ependymoma. It occurs most frequently in adults aged 20 to 50 years, with approximately 75% appearing in the cervical and thoracic segments of the spinal cord. The tumor tends to grow asymmetrically, lacks a capsule, and has poorly defined boundaries. Around 40% of spinal astrocytomas are characterized by histone H3 gene mutations (H3K27-altered), which are associated with central nervous system dissemination and poor prognosis.
MRI images often reveal spinal cord enlargement with eccentric tumor growth. The tumor may undergo necrosis and cystic degeneration, leading to heterogeneous signal patterns. Malignant astrocytomas frequently spread along the leptomeninges, causing asymmetric expansion of the spinal cord.
Due to the infiltrative growth pattern of the tumor, the surgical approach involves maximal resection of the tumor tissue while preserving neurological function, along with spinal canal enlargement and decompression to relieve pressure on the spinal cord. In cases of high-grade spinal astrocytomas, postoperative radiotherapy is recommended, as they are generally unresponsive to conventional chemotherapy.