Accuracy of stereotactic brain tumor biopsy: comparison of the histologic findings in biopsy cylinders and resected tumor tissue.

Appropriate treatment for intracranial mass lesions depends upon accurate morphological diagnosis. In 47 of 360 patients the findings in stereotactically obtained tissue cylinders were compared with tumor resection (n = 38) or autopsy (n = 9) tissue material to define the accuracy of our stereotactic biopsy method. These biopsies were performed using the LEKSELL CT stereotactic frame and a spiral needle which procured about 10-mm-long tissue cylinders. Usually, three to four successive biopsy specimens were taken along the target trajectory placed through the whole lesion and its margins according to the CT imagings. Final morphological diagnosis was exclusively based on the histological findings of permanent paraffin sections. In 42 cases (89%), the histological results in biopsy and resection/autopsy tissue were identical, including mainly cases of low and high grade gliomas as well as some brain lymphomas, metastases, and cases of inflammatory brain lesions (aspergillosis, toxoplasmosis). In 3 patients with a diagnosis of brain lymphoma and low grade glioma on the basis of the surgical specimens, stereotactic biopsy revealed only unspecific reactive tissue changes. In two cases of the early part of the study, sampling errors occurred. This study provides evidence for the high diagnostic accuracy of the established stereotactic biopsy method which is characterized by representative tissue sampling and histological processing of the specimens.