HYDROCEPHALUS ASSOCIATED WITH INTRAMEDULLARY LOW-GRADE GLIOMA - ILLUSTRATIVE CASES AND REVIEW OF THE LITERATURE

Over the past 15 years, eight children affected by intramedullary low- grade gliomas associated with hydrocephalus were treated at l'Hopital des Enfants Malades. In all cases the diagnosis of hydrocephalus was m ade prior to that of the spinal tumor. Neuroradiological examination o f all patients revealed contrast enhancement of the intracranial subar achnoid spaces. In six cases this was progressive, suggesting subarach noid spread of the tumor, which was confirmed in two cases by histolog ical examination. The authors analyzed 38 cases of intramedullary low- grade glioma associated with hydrocephalus that were reported in the l iterature. Fifteen of the cases had intracranial leptomeningeal seedin g. Several hypotheses have been proposed to explain this unusual assoc iation, such as 1) increase in cerebrospinal fluid (CSF) viscosity bec ause of elevated fluid protein content; 2) obliteration of the cistern a magna due to a rostral extension of the tumor; and 3) blockage of th e spinal subarachnoid pathways of CSF resorption. Two other theories s eem of particular interest. Bamford and Labadie suggested that the abn ormal presence of fibrinogen in the CSF and its transformation into fi brin at the level of the basal cisterns and a Pacchioni's granulation may alter CSF hydrodynamics. This mechanism alone is sufficient to ind uce hydrocephalus of the communicating type. In addition, as suggested by Maurice-Williams and Lucey, the resulting leptomeningeal fibrosis might predispose secondary implantation of neoplastic elements in the subarachnoid spaces of the intracranial compartment.