Intramedullary cysticercosis. Case report, literature review and comments on pathogenesis.

A 60-year-old woman developed progressive spastic crural paraplegia and global anesthesia and global anesthesia below T10, succumbing to urinary infection and bronchopneumonia 8 months after the onset of symptoms. At necropsy, the spinal cord was completely destroyed by a necrotic intramedullary cysticercus at T8. Six cysticerci were found in the brain. A review of the 17 published cases of intramedullary cysticercosis (including this one) showed this condition to be clinically indistinguishable from spinal cord tumours. The surgical prognosis was fair in 8 of 11 operated patients. The role of hematogenous and ventriculo-ependymal pathways in the pathogenesis of intramedullary cysticercosis was examined. The topographical distribution of intramedullary cysticerci (5 cervical, 12 thoracic, 2 lumbar, none sacral) was found to be statistically proportional to the blood flow to each of these regions; this favours the hematogenous route of infestation. The low spinal cord blood flow (100 times less than that to the brain), the type of vascularization of the cord (low calibre vessels under low pressure) and peculiarities of the cord tissue (such as its harder consistency) are all thought to be contributory factors accounting for the scarcity of intramedullary cysticerci. No evidence for an ependymal route of spread could be adduced.