Intramedullary spinal cord metastases are rarely the presenting manifestation of a previously undiagnosed neoplasms. We report such a case in which a subacutely progressive motor and sensory spinal cord syndrome was the initial problem. The differential diagnosis and the difficulties in distinguishing intramedullary from extramedullary mass lesions are discussed. The special features of tumors of the lung and their predilection for metastasis to the central nervous system are considered.