Giant intradural extramedullary spinal ependymoma, a rare arachnoiditis-mimicking condition: case report and literature review

Background and importance: Ependymomas are tumours arising from the ependymal cells lining the ventricles and the central canal of the spinal cord. They represent the most common intramedullary spinal cord tumour in adults and are very rarely encountered in an extramedullary location. Only 40 cases of intradural extramedullary (IDEM) ependymomas have been reported, all of which were diagnosed pre-operatively as IDEM ependymomas on contrast-enhanced MRI. Clinical presentation: We report a 23-year old male presenting with rapidly worsening signs and symptoms of spinal cord disease. A spinal MRI demonstrated a posterior multi-cystic dilatation extended between T1 and T12. Post-contrast sequences showed peri-medullar leptomeningeal enhancement and the diagnosis of spinal arachnoiditis was made. The patient underwent surgery and the spinal cord appeared circumferentially wrapped by an irregular soft tissue. The tissue was sub-totally removed and the pathological diagnosis was ependymoma WHO grade II. The patient experienced an excellent neurological recovery and no further treatments were administered. A small residue is now stable at 2.5 years follow-up. Conclusions: Giant IDEM ependymomas are rare entities and pre-operative diagnosis can be challenging in some cases. Surgery represents the main treatment option being resolutive in most cases.

Unusual cauda equina syndrome due to multifocal ependymoma infiltrated by lymphoma

Myxopapillary ependymoma is a rare tumour of the central nervous system (CNS); this subtype of ependymoma occurs most frequently in cauda equina, conus medullaris or filum terminale. The treatment consists of complete removal of the tumour including its capsule when possible since it is usually a solitary lesion. Non-Hodgkin lymphoma of the CNS is found in only 1.3% of cauda equina tumours. We report the case of a 62-year-old man who presented to our institution with progressive weakness of his right lower extremity, with numbness and paresthesia of both feet. He was suffering from one month of right sciatica. Lumbosacral MRI displayed two intradural extramedullary lesions, the first one was located posteriorly to L1-L2 and the second one was spreading from L4 to S2 presenting as a mucoid cyst in its superior part with hyperintense T2 signal, isointense on T1-weighted with high and homogeneous contrast enhancement in the inferior solid component. Imaging also found three additional intradural, extramedullary tumor formations with contrast enhancement, located respectively at C5-C6, C7 and T4. A L1-L2 and S1-S2 laminectomy was performed in emergency and total removal was achieved. Neuropathologist concluded that the tumor was a myxopapillary ependymoma infiltrated by large B-cell lymphoma. Although rare, this phenomenon (coexisting tumors within the same lesion) should be known by neurosurgeons because the occurrence of collision tumors affects the treatment and the patient's prognosis. In our case, two different types of tissue were mingled in the same location-this finding is very uncommon and has, to our knowledge, never been reported before.

Atypical benign melanotic thoracic intradural schwannoma

We discuss the 8th known case of a patient who presented with an intradural intramedullary spinal melanocytic schwannoma. In this report we will discuss the hypothesis regarding the pathogenesis of the development of intradural schwannomas, the imaging modality of choice and treatment options.