Cervical spondylotic amyotrophy with intramedullary cavity formation.

STUDY DESIGN: A case report. OBJECTIVE: To show that an intramedullary lesion was the cause of cervical spondylotic amyotrophy. SUMMARY OF BACKGROUND DATA: Cervical spondylotic amyotrophy is the clinical syndrome characterized by muscle wasting and weakness in the upper extremities without a remarkable sensory loss or spastic tetraparesis. It is still unclear whether the ventral roots or the anterior horn are selectively damaged. METHODS: Magnetic resonance imaging and delayed computed tomographic myelography were performed on a patient who showed severe wasting of the left triceps muscle without any sensory disturbance or long tract sign. RESULTS: On sagittal magnetic resonance images, a linear area was noted within the spinal cord at C6 and C7 spinal segments, which showed low signal intensity on T1-weighted image and high signal intensity on T2-weighted image. On axial T1-weighted image intramedullary low signal intensity area was observed, which was located in the left anterior horn. On axial T2-weighted image the area showed high signal intensity. A delayed (6 hours) computed tomographic scan after intrathecal injection of metrizamide revealed intramedullary enhancement in the area corresponding to the left anterior horn, which would represent cavitation or cystic necrosis. CONCLUSIONS: This is the first case report of cervical spondylotic amyotrophy, in which intramedullary lesion was confirmed only at the affected side of the spinal cord.