Pitfalls and problems in the histopathologic evaluation of stereotactic needle biopsy specimens.

When evaluating stereotactic needle biopsies, variabilities in the histology of brain tumor specimens should be taken into consideration. These include different histologic grades of malignancy in various areas of the same tumor (particularly gliomas), reactive tissues (mesenchymal or gliotic) focally overshadowing the tumor itself, and histologic formations within certain tumors, focally imitating neoplasms of another type.