[Histopathological changes of the human spinal cord--with special reference to latent lesions found in spinal cords of the aged].

The fifty-six spinal cords, which were randomly removed from the patients at the First Department of Pathology, National Defence Medical College, were histopathologically examined, to detect masked spinal lesions and some age-related changes. Pathological lesions were found in 55.4% of the cases, about half of which were opportunistic findings and had not caused any clinical symptoms. In these opportunistic lesions, benign neurogenic tumors (one cellular ependymoma from the central canal and ten schwannomas arose from anterior or/and posterior rootlets in 7 cases) were found predominantly in the higher age-group (17.9% of the cases above the age of 60 year had these tumors). Other opportunistic lesions were paraneoplastic syndrome, arachnoiditis ossificans, minimum-sized infarction in the spinal gray-matter, demyelination of the posterior white column, ganglio-radiculopathy and so on. As the basic changes of the cord related with aging process, attention was focused on the dystrophic axonal swelling and perivascular schwannosis. The incidence of dystrophic axonal swelling and of perivascular schwannosis were relatively correlated with patient's age. Hyalinization of arterioles in the spinal cord and the cauda equina were also observed in the higher age. It could be suggested that these vascular hyalinization would unfavorably influence the vulnerability of the spinal cord.