Intramedullary spinal cord metastasis associated with pencil-shaped softening of the spinal cord: case report.

A 57-year-old man presented with a pulmonary mass and subacute onset of paraplegia. Laboratory examination revealed an increased protein content in the cerebrospinal fluid and a normal myelogram. Autopsy disclosed epidermoid carcinoma in the left lower lobe of the lung, intramedullary metastasis at the midthoracic level, and a central pencil-shaped softening above and below the metastatic lesion. The pencil-shaped softening was an ischemic infarct rather than of hemorrhagic or congestive origin. The pathogenesis of this rare association may be explained by the hypothesis of a tumor embolus in the arterial circulation that feeds the center of the cord, producing metastasis. This embolus was followed later by a second embolus to a radicular artery, causing the pencil-shaped softening of the spinal cord.