Nonneoplastic intramedullary spinal cord lesions mimicking tumors.

OBJECTIVE: We report a group of nine patients with atypical, nonneoplastic intramedullary spinal cord lesions. By retrospectively reviewing these patients, we hoped to elucidate characteristics that would identify these patients as harboring nonneoplastic lesions before surgical intervention.

METHODS: We reviewed the histological findings of 212 patients undergoing surgery for intramedullary spinal cord tumors between 1989 and 1994. We identified nine patients with nonneoplastic lesions (4%); case histories and radiographs were reviewed.

RESULTS: All patients were evaluated preoperatively using magnetic resonance imaging. The extent of enhancement with gadolinium varied from homogeneous enhancement to no enhancement. All lesions showed marked T2 changes. There was a lack of significant spinal cord expansion associated with the lesions in all cases. All patients underwent surgery. The histology of the surgical specimens showed demyelinating lesions in four patients, sarcoidosis in two patients, amyloid angiopathy in two patients, and a mass of nonneoplastic inflammatory cells of unknown origin in one patient.

CONCLUSION: Although it was difficult to antecedently distinguish these lesions from neoplastic spinal cord tumors by case history and physical examination, the most consistent clue was absent or minimal spinal cord expansion on the preoperative magnetic resonance images.