Neuroimaging in the identification of low-grade and nonneoplastic CNS lesions

BACKGROUND- Certain central nervous system (CNS) lesions can be misconstrued histopathologically as high-grade or aggressive neoplasms when they are, in fact, low-grade processes for which surgery alone may be adequate therapy. Reactive lesions such as demyelinating disease can be misinterpreted as well and when diagnosed as a glioma, may be treated with radiotherapy. Complications of treatment, e.g., radionecrosis, are fostered by the long post-therapy survival periods permitted by low-grade neoplasms and, especially, nonneoplastic entities. REVIEW SUMMARY- As a benchmark against which any diagnosis of a CNS tumor should be reconciled is a set of neuroradiological findings that usually indicate a low-grade neoplasm or a reactive nonneoplastic entity. These eight specific radiological features are illustrated in the context of representative low-grade or nonneoplastic CNS lesions. CONCLUSIONS- An interdisciplinary approach, with reconciliation of any discrepancies between neuroimaging features and the pathological diagnosis, can minimize the possibility that patients with suspected CNS tumors will be overtreated.