Intramedullary spinal cord metastasis. Pathologic findings in five autopsy cases.

This report describes the pathologic findings in five autopsy cases with intramedullary spinal cord metastasis. In an autopsy series over a 30-year period, the incidence of intramedullary metastasis among the metastatic tumors to the spine was 3.5%, and the incidence among the central nervous system (CNS) metastasis was 4.2%. Primary site of tumor was the lung in four cases, and cancer of the thyroid was suspected in one case. On transverse section, the tumor was located mainly in the ventral part of the posterior horn and the medial part of the lateral column. Involvement was focal extending over one to six segments. In two cases, secondary hemorrhage occurred in the posterior horn or the posterior column. In three cases, central ischemic infarction was noted cephalad and caudad to the tumor metastasis. The mode of tumor spread to the spinal cord is not clear, but the autopsy findings in our series suggest that intramedullary tumor may result from hematogenous spread via the arterial circulation.