DIAGNOSTIC YIELD OF BRAIN BIOPSY IN NEURODEGENERATIVE DISORDERS

OBJECTIVE: The diagnostic yield and therapeutic implications of brain biopsy were determined in a series of 50 consecutive brain biopsies th at were performed in 48 patients between 1990 and 1995 at The Johns Ho pkins Hospital to assess progressive neurodegenerative disorders of un clear origin. METHODS: Severely immunocompromised patients and patient s undergoing biopsies for suspected neoplastic lesions were excluded f rom this analysis. Before surgery, the patients had undergone extensiv e laboratory and radiographic tests, including lumbar puncture (all 48 patients), electroencephalography (26 of 48 patients), magnetic reson ance imaging (all 48 patients), and angiography (17 of 48 patients). D espite the results of these studies, diagnoses could not be establishe d, and thus, brain biopsies were undertaken. RESULTS: Only 10 of the 5 0 biopsies (44 open procedures and 6 stereotactic procedures) led to d iagnoses, resulting in a diagnostic yield of 20%. An additional three biopsies (6%) were only suggestive of diagnoses. The results of 33 bio psies (66%) were abnormal but nonspecific, and the results of 4 (8%) w ere normal. Minor complications associated with biopsy occurred in fiv e cases (10%), and there were no deaths. Of the 10 patients whose biop sies were diagnostic, only 4 underwent meaningful therapeutic interven tion as a result of the procedure, resulting in an overall therapeutic benefit in only 8% of all the cases. An analysis of patient subgroups to elucidate a correlation with diagnostic biopsy revealed that patie nts with focal magnetic resonance imaging findings had the highest lik elihood of a diagnostic biopsy (odds ratio, 4.00). Electroencephalogra phy and laboratory abnormalities were not predictive of a diagnostic b iopsy. CONCLUSION: We conclude that the current diagnostic yield (20%) of brain biopsy for progressive neurodegenerative disorders is lower than that of earlier reports and that the therapeutic benefits of the procedure are limited.