Neuromyelitis Optica Mimicking Intramedullary Tumor
This 20-year-old woman had no other medical history. The patient had been suffering motor weakness in both upper extremities and radiating pain in both hands since 3 weeks ago. She experienced progression of pain, sensory changes, and lopsided motor weakness to the left side of the body. At the initial physical examination, a motor grade of both upper extremities was determined as grade 4 and no weakness was found in lower extremities. She was generally mildly hypertonic, although there was no Babinski sign or clonus. She complained of mild radiating pain in both hands, which was not one-sided with inexplicit dermatome. The patient underwent brain and whole spine MRI, which revealed a heterogeneously enhancing mass in the central posterior aspect of the spinal cord at the C1-6 level (). Brain MRI showed no specific findings. She was suspected of a tumorous condition, particularly ependymoma. Following this, she was admitted to our hospital for further evaluation of neurologic change. On the second hospital day, her motor function in both upper extremities suddenly deteriorated from grade 4 to 3. Cervical MRI was performed again, which revealed further extension of the hyperintense lesion on T2 weighted image and more intramedullary enhancing lesion on the T1 weighted image than that on the initial MRI image (). We hypothesized that the origin of neurologic deterioration was spinal cord compression by tumor bleeding. We immediately started intravenous steroid therapy and carried out total laminectomy C2-6 for decompression with surgical biopsy.\nWe performed C2-6 laminectomy and after opening the dura, the spinal cord was edematous but otherwise normal (). In the operation field, there was no tumor like lesion, discoloration or hypervascularization. We obtained frozen biopsy from a site near the lesion which was obtained consistent with astrocystic cell proliferation. Due to the gross normal finding and no tumorous frozen biopsy, we stopped the removal procedure of the mass lesion to prevent another potential spinal injury. The operation was closed by lateral mass screw fixation and fusion C2-6.\nOn the first postoperative day, her vital signs were stable, and suffered from nuchal pain, but her motor weakness remained the same. However, from the second postoperative day, motor weakness in both upper extremities became gradually better along with improvement of other sensory symptoms. On the twelfth postoperative day, permanent biopsy revealed abundant histiocytic collection, perivascular lymphocytic inflammation and reactive astrocytic proliferation. There was no evidence of a neoplastic process and no oligoclonal bands. The pathologist strongly suggested the diagnosis of neuromyelitis optica. Only then did we investigate her ophthalmic symptoms with a suspicion of another disease. She recalled her visual disturbance 5 years ago. Since then, there was no symptom until visit our department. We referred her to ophthalmology and revealed optic atrophy with disc pallor with optic neuritis on her left eye. Finally, her diagnosis was determined on NMO.\nOn the fourteenth postoperative day, her motor grade was improved to grade 5 and the patient could perform her daily tasks including eating food. We continued postoperative steroid treatment and started rehabilitation. After rehabilitation, she regained most of her upper-extremity motor functions and her ability to walk. Her pain significantly disappeared. When she was discharged from the hospital, there remained only mild nuchal pain. After 3 month from surgical intervention, her follow-up cervical MRI showed dramatic improvement ().