Cns Tumors

Abstract

Often, the radiologist is the first physician to diagnose a probable brain tumor, and description and differential diagnosis provided have profound implication for subsequent clinical decision making, so a radiologic accurate diagnosis can be very helpful in patient management. In 2016, the WHO released an update to its brain tumor classification system (not only based on microscopic information but also including molecular/genetic information) that included numerous significant changes. Several previously recognized brain tumor diagnoses such as oligoastrocytoma, PNET, and gliomatosis cerebri, were redefined or eliminated altogether. Conversely multiple new entities were recognized, including diffuse leptomeningeal glioneural tumor and multinodular and vacuolating tumor of the cerebrum. The glioma category has been significantly reorganized, with several infiltrating gliomas in children and adults now defined by genetic features for the first time.

The increased emphasis on genetic factors in brain tumor diagnosis has important implication for radiology. According to the 2016 WHO classification of CNS tumors, these lesions can broadly divide as following:

Diffuse astrocytic and oligodendroglial tumors Other astrocytic tumors (pilocytic astrocytoma, subependymal giant cell astrocytoma &…) Ependymal tumors Other gliomas (choroid glioma of 3rd ventricle, angiocentric glioma, astroblastoma) Choroid plexus tumors Neuronal and mixed neuronal-glial tumors Tumors of the pineal region

• Embryonal tumors

Tumors of cranial and paraspinal nerves

Despite the currently ongoing efforts, the medical treatment options for patients with brain tumors are limited and significant efforts are underway to find more effective and novel therapies for patients with brain tumors. The (RANO) working group is an international collaboration of neuro-oncologists, medical oncologists, radiation oncologists, neurosurgeons, neuroradiologists, and regulatory groups commissioned to develop objective and tumor-specific response criteria for various tumor subtypes. The development of reliable response assessment criteria is necessary to avoid false conclusions regarding the efficacy of the investigated drugs (responders and non-responders). In the first part of the session we will have a brief discussion about 2016 updates to the WHO brain tumor classification and The Response Assessment in Neuro-Oncology (RANO). In other parts we will discuss interactive case presentations about different types of CNS tumors according to new WHO classification.