Retrograde pyramidal tract degeneration in a patient with cervical haematomyelia.

Retrograde pyramidal tract degeneration has been described only very rarely in the human central nervous system. In most of these cases the thoracic or cervical corticospinal tracts were shown to have degenerated following long-standing, lower spinal cord lesions. In a 67 year old man, who lived 2 years following the rupture of a mid-cervical cavernous angioma, we observed such degeneration which reached as high as the pons. This axonal dissolution was much less manifest above the ponto-medullary junction. Large pyramidal cells of Betz were not identified in the precentral gyrus, suggesting that the parental soma of the damaged axons had undergone atrophic changes. Furthermore, the involvement of the so-called aberrant pyramidal tract in the pontine medial lemniscus indicated that retrograde degeneration had occurred there as well.