Clinical and neuropathological study of six patients with spastic paraparesis associated with HTLV-I: an axomyelinic degeneration of the central nervous system.

Between 1990 to 1994, 6 TSP/HAM patients, 3 women and 3 men with an average age of 57.1 years (39 to 76 years old), who died in the Salvador Hospital were submitted to postmortem examination. The mean time of paraparesis was 7 years (3 to 17 years), and 2 patients had pseudobulbar signs. Three cases had macroscopic atrophy of the spinal cord. Histologically, all cases had lesions in the pyramidal tracts and 4 cases showed somatotopic lesions of the Goll's tracts which followed a "dying back" ascendant and descendant distribution, respectively. In 2 cases, both of which had intellectual impairment, demyelination of the subcortical and parathalamic areas was observed without U fiber involvement. Abnormal vessels with gross thickening of the adventitia, many of them with lymphocytic cuffs, were seen everywhere, especially in the spinal cord, brain stem, midbrain and meninges, but no relation between these findings and the parenchymal lesions was observed. Also, in the cases with posterior column involvement, neuronal changes and proliferation of satellite cells in the dorsal ganglia were found. All cases showed histological sialoadenitis and none had inflammatory muscle changes. We conclude that the lesions affected the neuraxis in a systemic axial fashion as in degenerative diseases, and did not seem to be secondary to vascular or inflammatory abnormalities.