Gliosis Versus Glioma and the Most Critical Issues in Recognizing and Grading Gliomas

In surgical neuropathology, as in other areas of pathology, before making a diagnosis of “tumor” the possibility of a non-neoplastic process should be fully considered and excluded. “Gliosis” is a non-specific change that is encountered quite often in routine practice and may accompany both neoplastic and nonneoplastic conditions. Because there is usually some type of pathological process that stimulates gliosis, correct interpretation of biopsy or resection specimens from the central nervous system must begin with knowledge of basic clinical information (age, duration of symptoms, location of the lesion), correlation with imaging studies, and evaluation of any clinical laboratory analyses. Only after a tumor diagnosis is established with certainty can there be an enlightened assignment of glioma type (infiltrating vs. focal; astrocytic vs. oligodendroglial) and grade (low vs. high).