CSF beta-glucuronidase assay in the diagnosis of neoplastic meningitis.

The clinical value of CSF beta-glucuronidase assay in the differential diagnosis of chronic meningitis had been investigated over the past 20 years. Significant (P < .001), often marked, elevation of the enzyme level was found in the first sample submitted in 29 of 30 cases of neoplastic meningitis, irrespective of treatment (mean, 324 units), and in 12 of 14 untreated cases with meningeal lymphoma (mean, 174 units). On the other hand, untreated patients with chronic meningitis of other etiologies had significantly lower of other etiologies had significantly lower levels of enzyme elevation, eg, leukemic meningitis (mean, 46 units), fungal meningitis (mean, 41 units), and tuberculous meningitis (mean, 79 units). In the few cases of chronic meningitis studied during appropriate therapy, a tendency toward a decrease in enzyme activity was noted, thus offering further diagnostic support. In our opinion, the finding of a marked elevation of beta-glucuronidase activity in a patient with chronic meningitis is presumptive evidence of neoplastic etiology.