Characteristics of cisternal cerebrospinal fluid associated with primary brain tumors in the dog: a retrospective study.

Results of cisternal CSF analyses of 77 dogs with primary brain tumors (1970 to 1984) were examined retrospectively. The types of primary brain tumors were astrocytomas, choroid plexus papillomas, ependymomas, meningiomas, and oligodendrogliomas. Fifty-three dogs had complete CSF analyses performed (total WBC count, total protein content, and pressure). Of these 53 CSF, 39.6% had a pattern of change consistent with current descriptions of CSF associated with brain neoplasia. Results of the remaining 60.4% of the 53 CSF were normal (9.4%) or had an atypical pattern of abnormality (50.9%). The CSF associated with meningiomas was unique in having CSF with a WBC count greater than 50 cells/microliter and a WBC differential count greater than 50% polymorphonuclear (PMN) cells. Within the meningioma group, a predominance of PMN cells in the CSF correlated with necrosis or PMN cell infiltration of the tumors. Additional correlations between specific CSF characteristics and histologic features of the tumors could not be made. Statistical analysis of the 77 CSF revealed that the mean CSF total WBC count of the oligodendroglioma group was significantly less than the mean WBC count of the choroid plexus papilloma group and the meningioma group. The mean CSF total protein contents of the astrocytoma group and the meningioma group were significantly less than the mean protein of the choroid plexus papilloma group. The mean CSF pressure of the tumor groups was not significantly different. For all 77 tumors, the most common abnormality was an increased total protein content (69.4%); the least common abnormality was an increased total WBC count (41.3%).(ABSTRACT TRUNCATED AT 250 WORDS)