Intramedullary spinal cord metastases, mainly of nonneurogenic origin.
The clinical data and imaging studies of 12 patients with intramedullary metastases were reviewed retrospectively to see if these lesions had a typical radiographic appearance and to determine the sensitivity of the various radiologic examinations. The lesions were identified antemortem by either myelography, CT, MR, and/or intraoperative spinal sonography (IOSS). Final diagnosis was based on biopsy material from either the spinal cord lesion, another metastatic site, and/or the primary tumor. Ten patients had primary tumors located outside the central nervous system, while only two patients had primary brain tumors. Metrizamide myelography and CT demonstrated a definite intramedullary mass in nine of 11 patients. In five patients the mass was relatively small, well-defined, single, and resembled a primary spinal cord neoplasm. In the other four patients, longer and sometimes several segments of the cord were involved. These appeared irregular and nodular and were often associated with intradural lesions at separate sites. MR detected not only enlargement and abnormal signal in the cord but also clinically unsuspected brain lesions. IOSS localized lesions for biopsy and monitored tumor resection. These various imaging procedures showed that cord metastases were often more extensive than anticipated clinically. Spread of tumor into the spinal and intracranial subarachnoid space was common. Imaging of the entire spinal canal and brain, preferably with MR, is therefore recommended to aid in diagnosis, prognosis, and treatment.