giovedì 22 dicembre 2005

Spinal ependymoma






Findings

Sagittal T1-weighted contrast-enhanced image shows a mass in the cervical region, which enhances at the level of C4 and at C5-6 (Figure 1). On these images alone, it is difficult to differentiate from nonenhancing soft tissue; but, there are three complex cysts, which are hyperintense to CSF - above, below, and between the areas of enhancement (Figure 1). There is also a dilated intramedullary cyst below the fourth ventricle, which is of CSF intensity (Figure 1).
The sagittal T2-weighted images of the cervical and thoracic spine show hemosiderin staining with a “cap sign” at the superior margin at the level of C4 and the inferior margin at the level of T3-4 (Figure 2 and Figure 3) of the tumor. There is hemorrhage superiorly in complex cysts (Figure 2). There is also an intratumoral cyst (Figure 2 and Figure 3).


Diagnosis: Spinal ependymoma


Ependymomas are the most common intramedullary spinal cord tumor in adults. The highest incidence is seen in the third through fifth decades of life. Patients sometimes are given a delayed diagnosis because of the mild nature of symptoms which can be chronic in nature. Most commonly, the symptoms are neck and back pain with sensorimotor symptoms, and bowel and bladder incontinence being less frequent. These tumors arise from ependymal cells lining the canal and are usually histologically benign. Ependymomas are well circumscribed, often surrounded by a thin delicate capsule, and are noninfiltrating. Frequently, areas of necrosis and hemorrhage are present in these tumors.

In the spinal cord, ependymomas most commonly occur at the level of the cervical spine (44%), sometimes extending to the upper thoracic spine (additional 23%). Less commonly, these tumors involved the thoracic cord alone or the conus medullaris. Most ependymomas are hypointense to isointense to spinal cord on T1-weighted images. There may be focal T1 hyperintense areas corresponding to areas of hemorrhage. On T2-weighted sequences, these spinal cord tumors demonstrate high signal in cystic areas with up to one-third containing the "cap sign" of hypointense signal representing a hemosiderin at the rostral and caudal margins. In addition, ependymomas are commonly seen to enhance with contrast. Usually, there is associated cord edema present. A subtype, myxopapillary ependymoma, is seen in the filum terminale and subcutaneous sacrococcygeal region which appears multilobulated and encapsulated.

Prognosis is generally good with a 5-year survival of 82%. The treatment of choice is microsurgical resection with radiation therapy given for incomplete resection, recurrence, or disseminated disease. Metastatic disease can be seen in the lungs, retroperitoneum, and lymph nodes.

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