Intramedullary Spinal Cord Metastasis in Renal Cell Carcinoma: A Case Report of the Surgical Experience
A 44-yr-old male was diagnosed with renal cell carcinoma on the left kidney with lung metastasis and was treated by molecular target agent therapy (Sunitinib, 37.5 mg/day, per oral, 4/2 week scheduled) without surgery (). After 6 months later from a diagnosis of RCC, he presented rapid progressive paraparesis and both leg numbness. His motor power of both hip flexion was 3/5 (0; none, 5; normal) and other distal lower extremity was 4/5.\nMagnetic resonance image (MRI) of the spine revealed intramedullary mass lesion on T12 level (). This lesion showed iso-signal intensity (SI) on T1 weighted images (T1WI) and high-SI on T2 weighted images (T2WI) with significant rim enhancement after gadolinium based contrast agent injection. Extensive edematous infiltration on intramedullary space which shows high SI on T2WI was checked up to the upper thoracic level.\nFocal radiotherapy on the spine was initiated due to his refusal for surgery. Over the following 10 days during radiotherapy, his neurological deficit rapidly progressed to 2-3/5 on the right lower extremity and 0-1/5 on the left lower extremity. Under the umbilicus level (sensory dermatome level T10), all components of sensory, including pain, touch, vibration and temperature, were decreased and painful paresthesia on both lower extremities was checked. He also complained of urinary incontinence and decreased anal sphincter tone was checked on the neurological examination.\nFor the rapid progression of neurological deficit, emergency surgery was performed. Under the neural integrity monitoring (NIM-SPINE, Medtronic Sofamor Danek, USA), laminectomy of T10, T11, and T12 was performed. Under the intra-operative ultrasonographic view, mass lesion was confirmed near the T12 pedicle. After midline dural incision, arachnoid membrane was opened. For abnormal lesion was not checked on the surface of the spinal cord, posterior myelotomy through midline posterior sulcus was performed. After gentle dissection, soft and grayish colored tumor lesion distinguishable on microscopic view was checked. Microsurgical removal of the tumor with the use of Cavitron Ultrasonic Aspirator (CUSA, Valleylab, USA) was performed. On the neural integrity monitoring, no abnormal signal change was checked during the whole operation.\nAfter surgery, painful paresthesia of both lower extremities was immediately improved on the visual analogue scale (VAS) from 7 to 2. Significant improvement of motor power to self-ambulation with walking stick was checked on an outpatient follow-up after 2 months later from surgery. Follow up MRI imaging after 2 months later from surgery, enhancing mass lesion was nearly total removed and edematous infiltration on T2WI was significantly reduced ().\nOn a histological examination, it was composed of nests of clear tumor cells with intermediate nuclear grade vascular meshwork and showed a strong cytoplasmic reaction within tumor cells in immunohistochemical staining for both cytokeratin and vimentin ().\nOn the neurological examination of 6 months from surgery, the motor power of both lower limbs was improved to 3-4/5, and he could walk by himself with the assistant of a walking stick.