IMPORTANCE OF IMAGE-GUIDED STEREOTAXIC BIOPSY TO CONFIRM DIAGNOSIS INAN ONCOLOGICAL SETTING

Background: In current practice, the neurosurgical community relies he avily on computed tomography (CT) and magnetic resonance imaging (MRI) for making the diagnosis of brain lesions, especially when surgically inaccessible. However, the specificity of these neuroimaging modaliti es remains limited, and errors in diagnosis are frequent. In an attemp t to ascertain how often the diagnosis based on imaging studies is pro ved wrong by biopsy, we reviewed the findings from 100 consecutive ste reotactic biopsies performed in an oncological setting. Method: The re cords of 100 consecutive stereotactic biopsies were postoperatively re viewed. The preoperative clinical and radiologic differential diagnose s were compared with diagnosis made on tissue retrieved by biopsy. Res ults: In 19% of patients, the preoperative clinical and radiological d iagnoses and postoperative diagnosis were different, and reliance on b rain imaging data alone would have led to an incorrect tentative diagn osis and the wrong choice of treatment. Conclusions: The high rate of discrepancy between clinical and radiological diagnoses on the one han d and biopsy-proven diagnosis on the other hand is a compelling reason to establish tissue diagnosis. Stereotactic biopsies of brain lesions are relatively safe and should be performed in cases where tissue cha racteristics affect prognosis, where therapy carries an inherent risk, and in those patients under treatment for cancer or immune deficienci es in whom there is an unusually broad differential diagnosis.