Totally Ossified Metaplastic Spinal Meningioma
A 61-year-old woman had a 1-year history of numbness in right lower extremities that progress bilaterally and ascend to his half lower body below the umbilicus. She also noticed progressive urinary incontinence without weakness in lower extremities. Neurological examination revealed a hypoesthesia to touch and pain from T10 to S2 level. Also, she had positive sign in Romberg test. Both patella and ankle reflexes were hypoactive and the Barbinski signs were bilaterally negative. Computed tomographic images without enhancement show a large hyperdense intradural round mass occupying the whole spinal canal at T9-10 level (). Magnetic resonance imaging revealed a large T9-10 intradural extramedullary mass that was hypointense to spinal cord on T1- and T2-weighted sequences, partial enhancement was apparent after Gd administration (). The spinal cord was severely compressed and displaced toward the right.\nUnder general anesthesia, the patient was positioned prone after placement of transcranial muscle motor evoked potentials (Tc-MEPs) and somatosensory evoked potentials (SSEPs) monitoring devices. A T9-10 laminectomy was performed after midline splitting of T9-10 spinous process. The dura mater was exposed and the tumor location has been confirmed at the T9-10 level by ultrasonography. An operative microscope was used during opening the dura, the dura was incised at the midline, exposing a hard and totally ossified, round dural-based extramedullary mass compressing and displacing the spinal cord to the right. We performed tumor debulking with an ultrasonic surgical aspirators. Adhesions between the tumor and the spinal cord were meticulously separated after adequate internal decompression of the tumor (). Surgery proceeded slowly and en block resection of the tumor was performed without significant changes in MEP monitoring. Using the microscissors and microdissector, the tumor and its dural attachment at the left side were removed from the spinal cord. The dural attachment was thoroughly coagulated using bipolar cauterization. A gross-total resection could be achieved with en block manner. Finally, the dura was closed with a Gore-Tex membrane (W. L. Gore & Associates, Inc., Flagstaff, AZ, USA) as an intradural sheet to prevent arachnoiditis.\nHistopathological findings demonstrated delicate oval nuclei and inconspicuous nucleoli, lightly eosinophilic cytoplasm, proliferate forming cellular whorls. Within the tumor, marked heterotopic ossification occurs without psammoma bodies (). The findings were consistent with spinal metaplastic meningioma. Postoperative MR imaging revealed no evidence of residual tumor. Three days after surgery, the patient had regained full urinary continence, ambulated without an assistive device, and exhibited normal motor strength with residual numbness in her both feet. Prior to discharge from the hospital on postoperative day 31, she could ambulate without a cane and both leg numbness and sensation of pain as well as touch had improved. However, left foot numbness persisted and it caused her hard to go up the stairs for herself. She benefited from a short stay in the inpatient rehabilitation unit.