Intramedullary Spinal Cord Tumors Workup

Updated: Jan 30, 2020
  • Author: Alfred T Ogden, MD; Chief Editor: Brian H Kopell, MD  more...
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Workup

Imaging Studies

MRI produces exquisite detail of the spinal cord. Most tumors are isointense or slightly hypointense compared with the normal cord signal. Tumors generally exhibit some enhancement with gadolinium, and this enhancement may be homogeneous or irregular, as depicted in the images below. Contrast-enhanced MRI, shown in the images below, is very sensitive for tumors and may disclose minute lesions.

Plain radiographs of the spine cannot diagnose an intramedullary tumor but may be useful for surgical planning if the tumor is associated with a deformity.

Myelography has now been surpassed by MRI and is used mainly when MRI is not available.

Spinal angiography and embolization can be useful in cases of hemangioblastoma.

The first panel shows a cervical syrinx. The diffe The first panel shows a cervical syrinx. The differential diagnosis for syrinx includes trauma, Chiari malformation, and dysmerogenesis. A syrinx can also be the by product of a tumor, which may be distant anatomically from the associated syrinx. The second panel shows a small enhancing ependymoma of the thoracic spine that was found during the workup for the cervical syrinx.
This is a sagittal image of an enhancing conus med This is a sagittal image of an enhancing conus medullaris lesion in a 45-year-old man who presented with midline back pain. This hemangioblastoma was removed completely. The patient remains neurologically intact, and imaging of his neuroaxis did not reveal other lesions.
Axial image of hemangioblastoma. Axial image of hemangioblastoma.

Determining whether an abnormal MRI definitively indicates the presence of a tumor can be problematic. MRI alone does not guarantee an accurate diagnosis in every case, and the clinical history and neurologic examination help avoid unnecessary surgery on multiple sclerosis plaques or vascular or inflammatory myelitis. The spinal cord appears enlarged when a tumor is present, while inflammatory lesions result in a normal or minimal increase in cord size appearance. In cases where a syrinx is noted, as depicted in the first image above, one must distinguish a primary syrinx from a tumor-associated syrinx. Therefore, a search for a Chiari malformation or abnormal contrast enhancement must be undertaken.

Some tumors have a tendency to occur in multiple areas, and imaging the entire neuroaxis may be indicated (eg, hemangioblastoma).

The differential diagnosis of a patient presenting only with back pain is legion and most commonly is the result of degenerative spine disease. The contrast-enhanced MRI characteristics of the spinal cord have greatly simplified the diagnosis of intrinsic spinal cord tumors. However, diagnosis still can be problematic, as follows:

  • Syrinx - Multiple causes, including tumor

  • Multiple sclerosis - May show multiple lesions of neuraxis

  • Transverse myelitis

  • Cord infarction

  • Abscess

  • Tuberculosis

  • Hematoma

  • Herniated disk

  • Cord contusion

  • Extradural neoplasm

  • Intradural extramedullary neoplasm

  • Arteriovenous malformation and fistulae

  • Sarcoidosis and other granulomatous diseases, as depicted in the images below

    This is a sagittal image of an enhancing cord lesi This is a sagittal image of an enhancing cord lesion in a 41-year-old man with a rapidly progressing severe quadriparesis. A biopsy showed this to be sarcoidosis. Following treatment with steroids, he is now ambulatory with assistance.
    Axial image. Axial image.

 

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Histologic Findings

Ependymomas

Ependymoma is a common primary neoplasm of the spinal cord and filum terminale. It is the most common primary glial neoplasm of the spinal cord, constituting 50-60% of intramedullary cord neoplasms. They frequently present in middle age but can occur at any age. Ependymomas are believed to be slow-growing tumors. Because of their tendency to compress adjacent parenchyma, patients with spinal ependymomas usually experience gradual symptoms because of slow progression, making early diagnosis difficult. [12]

Ependymomas occur anywhere in the cord and are commonly in the conus medullaris, where an exophytic component may be present. They rarely change growth characteristics and metastasize.

Lesions are characteristically hypovascular, well circumscribed, and noninfiltrative of the surrounding cord. Sometimes they are associated with a cystic "capping” of the tumor poles. Symptoms are due to a chronic dilation of neural tissue rather than infiltration. Complete resection often results in cure.

The first panel shows a cervical syrinx. The diffe The first panel shows a cervical syrinx. The differential diagnosis for syrinx includes trauma, Chiari malformation, and dysmerogenesis. A syrinx can also be the by product of a tumor, which may be distant anatomically from the associated syrinx. The second panel shows a small enhancing ependymoma of the thoracic spine that was found during the workup for the cervical syrinx.

Astrocytoma

Astrocytoma accounts for 6-8% of all spinal cord tumors and is primarily low grade. It occurs in both adult and pediatric populations, with the most common presenting symptoms being back pain, sensory dysfunction, or motor dysfunction. [11, 5, 6]  In children, astrocytomas are the most common tumor type, accounting for around 60% of all intramedullary spinal tumors, and the mean age of presentation is 5-10 years. Sometimes they are associated with microcysts or syringes. The pilocytic varieties are well differentiated and tend to be indolent, with a definable surgical plane.

The remainder of low-grade astrocytomas are infiltrative and impossible to resect completely. Residual tumor often has an indolent course, and controversy exists in the management of such tumors.

Fortunately, anaplastic astrocytoma or glioblastoma is rare. These malignant tumors exhibit rapid growth, are locally invasive, and may seed the CSF. Distinguishing between tumor and normal cord is difficult. Aggressive surgical resection has a controversial role with such tumors.

Hemangioblastomas

Hemangioblastomas are benign, slow-growing, highly vascularized tumors of the central nervous system, with the most common location being the posterior fossa. Hemangioblastomas are often associated with von Hippel-Lindau disease. [13]  Hemangioblastomas often have an associated syrinx and occur in multiple locations. These should not be removed in a piecemeal fashion because significant bleeding may ensue, increasing the risk of the procedure. Removal of the lesion is considered curative.

Developmental tumors

Dermoid, epidermoid, and teratoma are slow-growing neoplasms with a thoracolumbar predominance. Some dermoids of the conus medullaris have been attributed to lumbar punctures that carry in cutaneous tissue.

These tumors may have a dense capsule, precluding complete removal, although this may be compatible with prolonged symptom-free survival. When complete removal is unobtainable, debris produced by the tumor may cause an early recurrence of symptoms.

Lipoma

Not true neoplasms, lipomas present in the first 3 decades of life when fat is being deposited. They may be associated with cutaneous abnormalities. Loss of total body fat may be necessary to reduce the mass of the tumor.

Fibrous adhesions to the cord make total removal difficult. Removal is not the goal of surgery. The carbon dioxide laser is particularly useful for this lesion. [17]

Other tumors

Unusual lesions include subependymoma, ganglioglioma and intramedullary schwannoma, and neurofibroma. Management of low-grade lesions parallels other indolent lesions. Metastatic lesions to the spinal cord are unusual. 

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