Raised intracranial pressure due to spinal tumours: 3 rare cases with a probable common mechanism.

Three cases are reported of raised intracranial pressure associated with spinal tumours. The theories which have been advanced to explain this complication are discussed and it is suggested that in many of the reported cases the underlying mechanism may have been intracranial spread of the tumour and not a blockage of the cerebrospinal fluid pathways with proteinaceous deposits, as has been widely maintained. Autopsy revealed the former process to have operated in 2 of the 3 cases and it may have done so in the third. Two cases had unusual features in common: they were malignant schwannomas (a very rare spinal tumour) and they had both developed within the field of irradiation given for benign conditions many years previously.