Intradural Extramedullary Spinal Ependymoma: A Case Report of Malignant Transformation Occurring
A 23-year-old woman was admitted to our institution on January 2009. Her symptoms included a backache around her right shoulder, paresthesia in the left lower limb, pain in the left abdominal region, and difficulty walking smoothly (as a result of the backache and pain). The patient had first noticed the backache 4 months before admission, and her neurological status progressively worsened.\nNeurological examination revealed slightly motor weakness of left lower limb. She had sensory disturbances of above. Examinations were negative for the Romberg sign, with bilateral Babinski's sign. Deep tendon reflexes were nearly symmetrical in the lower extremities. Urinary function, rectal tone, and perianal sensation were normal.\nCranial computed tomography (CT), and abdominal, chest X-ray were within normal range, magnetic resonance imaging (MRI) of the thoracic spine () showed a posterolateral intradural extramedullary mass compressing the spinal cord at the T4-T6 levels. The mass was of low intensity in medullary tissue for T1 imaging and of slightly high intensity in the T2 sequence, with homogeneous enhancement after gadolinium injection. Its limits were well defined, occupying 60% of the posterior and left spinal canal without bone destruction or foramen invasion, suggesting schwannoma or meningioma as the first option. No other lesions were present along the neuroaxis, including the posterior fossa.\nBecause the tumor was present in the left spinal canal, a left hemilaminectomy from T4 to T6 () was performed, uncovering an intradural extramedullary encapsulated mass. We determined that the tumor was not connected to the dura mater or spinal roots, and had not infiltrated the spinal cord. Only mild adhesions to the spinal pia mater were found and were carefully stripped away.\nA gross total resection was completed without damage to the medulla, using an ultrasonic surgical aspirator under an operating microscope.\nAnatomic-pathologic studies were performed. Immunohistochemical examination () demonstrated strong immunopositivity with anti-glial fibrillary acidic protein, especially in perivascular pseudorosettes, but there was no immunostaining with the epithelial membrane antigen. Neither cystic degeneration nor anaplastic change was present, but the Ki-67 index was 5% to 10%. Histological examination revealed a World Health Organization (WHO)-grade 2 ependymoma with hypercellular nodules that demonstrated a high Ki-67 index.\nThe patient's neurologic condition improved after surgery and she was discharged from the hospital with mild paresthesia and pain in the left abdominal region. Neither radiotherapy nor chemotherapy was performed. We carried out close follow-up by MRI ().\nOne and a half years later, the patient's physical and neurological condition had worsened, with increased pain in the left abdominal region. MRI of the thoracic spine () uncovered a recurring mass at the T4-T5 levels: a posterior intradural extramedullary tumor.\nA T4-T6 laminectomy () was performed; the tumor was removed and classified as a WHO-grade3 anaplastic ependymoma (). The patient was started on a course of regional spinal cord radiotherapy, which was 50.4 Gy/28 Fr. The symptoms in the left abdominal region decreased. Neither worsening nor deterioration was observed after surgery and radiotherapy treatment, with the patient achieving tumoral control and clinical stabilization with a total follow-up of 17 months after the recurrence.