Stereotactic brain biopsy: An audit of sampling reliability in a clinical case series.

Stereotactic brain biopsy is the current gold standard procedure to obtain a neuropathological diagnosis. An audit of 207 stereotactic cases, between January 1997 and December 2000 was carried out. The aim was to determine the optimum number of target sites required to make the final diagnosis and thereby set up recommendations for future practice. The overall diagnostic success rate was 89.3%. A significant positive correlation between the number of targets taken and the probability of achieving the final diagnosis was seen. In a subset of glioblastoma cases 96.1% of the tumours could have been confidently diagnosed on the basis of any two of the targets chosen, although often more targets were taken than this. The recommendations made by the audit were: (i) in cases where it is suspected the lesion does not require grading, one target site should be taken and further sites should only be taken if the first proves to be non diagnostic; (ii) in suspected glial series tumours, two targets should be routinely taken, with further sites taken only if these prove inconclusive on intraoperative smear.