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Persistent hydrocephalus following removal of choroid plexus papilloma of the lateral ventricle.

We report a case of choroid plexus papilloma of the left lateral ventricle, which illustrates the difficulties of diagnosis of these tumours with air studies in advanced hydrocephalus. The hydrocephalus was apparent at the age of three months, but ventriculography failed to reveal the true nature of the communicating hydrocephalus. A ventriculocaval shunt was inserted, but the hydrocephalus progressed, in spite of the fact that the shunt was functioning well. The diagnosis of a papilloma of the choroid plexus was made after performing a CT examination at the age of 3 1/2 years. In spite of radical tumour removal, three years after the operation the axial computer tomography revealed a persistent hydrocephalus, but no recurrence of tumour. To control the hydrocephalus, a bilateral shunt with low pressure valve was necessary. With reference to the literature we discuss the possible causes of persistent hydrocephalus after surgical removal of these tumours. The majority of authors concluded, that because of repeated subarachnoid bleeding by these tumours, it must be a form of aresorptive hydrocephalus. The persisting hydrocephalus is probably caused by an increase of the CSF outflow resistance because of a distal CSF-pathway obstruction.