Intramedullary spinal cord metastasis. A clinicopathological study of 13 cases

A retrospective autopsy study of 627 patients with systemic cancer disclosed 153 patients with metastasis to the central nervous system (CNS) and 13 patients with intramedullary spinal cord metastasis (ISM). Thus, the frequency of ISM was 8.5% of cases of metastasis to the CNS and 2.1% of all cases of cancer. Bronchogenic carcinoma accounted for 11 cases of ISM, and breast carcinoma and melanoma for the other two. There were two distinct patterns of spinal cord involvement, indicating spread of tumor to the cord by two different routes. In nine of the 13 ISM patients a metastasis was found deep within the spinal cord, unassociated with leptomeningeal carcinomatosis; this most likely resulted from hematogenous spread of tumor from a pulmonary source. In the other four patients there was focal or multifocal direct extension of leptomeningeal metastatic tumor across the pia into the parenchyma of the cord. Only four of the 13 patients had a clinical myelopathy; in three of these four this was the presenting feature of an occult lung cancer.