The value of per-operative smear examination during stereotactic biopsy.

Sixty-two consecutive CT-directed stereotactic biopsies were studied retrospectively to determine the value of the per-operative smear examination. Overall, in 69% of cases the immediate smear result agreed with the definitive histology. However, a smear diagnosis of malignant glioma was more reliable than that of metastasis (with 100% and 55% agreement with the final result respectively). In those cases where the final histological diagnosis was that of malignant glioma, immediate smear preparations taken from the hypodense centre were found to be more reliable than those taken from the enhancing edge.