September 5, 2019
A 35-year-old man with a 1 year history of left, upper extremity numbness. He also experienced a progressive burning sensation, which then involved the entire T10-T11 dermatome.
Spinal Cord Subependymoma
- Background
- Ependymal tumors encompass a group of 9 subtypes that can occur anywhere along the neuro axis, depending on location, histology, and genetic/epigenetic markers.
- Supependymomas typically occur in the fourth and lateral ventricles in adults. Spinal cord subependymomas are rare and tend to occur in middle and older age individuals.
- They are slow growing, World Health Organization (WHO) Grade I tumors.
- They comprise 2% of all symptomatic spinal cord tumors. If found in the spine, they are usually intramedullary in the cervical or cervicothoracic region and eccentrically located.
- Clinical Presentation
- Subependymomas tend to be slow growing, noninvasive tumors. They can be asymptomatic and found incidentally or on necropsy.
- Various neurologic deficits have been reported depending on their location.
- If located in the ventricles, they may present with symptoms of obstructive hydrocephalus.
- Key Diagnostic Features
- Subependymomas are best visualized with MRI and tend to be eccentrically located in the spinal cord.4
- On MRI, they are typically T2 hyperintense and T1 hypo to isointense to white matter. The T2 signal depends on the degree of cystic changes and if there is any associated hemorrhage or calcification in the tumor. They typically do not enhance, but slight enhancement may be present.
- Differential Diagnosis
- Spinal cord astrocytoma: The median age of diagnosis is slightly younger, with adults' astrocytoma’s occurring at a mean age of 35. They are the most common spinal tumor in the pediatric population. Astrocytomas tend to also be poorly defined with variable, but usually greater degree of enhancement.
- Spinal cord ependymomas: Typically T1 isointense, T2 hyperintense, and usually exhibit heterogenous enhancement. They have a central location and are well circumscribed lesions with a cleavage plain and an associated syrinx.
- Spinal cavernous malformation: They have no enhancement and show blooming on T2* imaging indicating hemosiderin deposition.
- Treatment
- Gross total resection with a good prognosis if total resection is achieved. The goals of surgery are to obtain a diagnostic sample, to achieve spinal cord decompression, and to provide long term control.
- The role of additional therapies such as chemotherapy and radiation is unclear, however radiation may be of some benefit in residual or recurrent disease.
