Objective Threshold for diagnostic brain biopsy reflects variations in perceived risk and diagnostic utility. The aim of this study was to review the indications for, complications and outcome of diagnostic brain biopsies performed between 2003 and 2008 in a UK regional neuroscience centre.

Methods Subjects were retrospectively identified using theatre log books and histopathology reports. Case records were analysed jointly by a neurologist and neurosurgeon. Cases were excluded when there was a clear preoperative diagnosis of malignancy or infection.

Results Fifty-six biopsies were performed in 52 patients; representing 13% of all (432) brain biopsies. There were no permanent deficits or deaths. Histopathological reports were classified as definitive (44%), suggestive (20%) or nondiagnostic (36%). Ultimately, biopsy contributed to a confident diagnosis in 75% of patients, and to a change in patient management in 63%; it was considered clinically “useful” in 77%. Successful biopsy of a radiologically identified surgical target increased the proportion of biopsies considered diagnostic to 60% whereas blind biopsy was nondiagnostic in 72%. A significant proportion of patients had progressive disease and/or died but this was not uniformly the case; 21% stabilised and 27% improved.

Conclusions Brain biopsy for otherwise undiagnosed neurological conditions carries relatively little risk and may have significant implications for diagnosis and patient management in carefully selected cases.