Histological approach to neuronal and mixed neuronal-glial tumors of the central nervous system

The 2016 updated World Health Organization Classification of Tumors of the Central Nervous System shows an increasing number of entities under the classification of neuronal and mixed neuronal-glial tumors. Despite being a biogenetically heterogeneous group of tumors, the members frequently display some overlapping histological and clinical features, leading to diagnostic dilemmas among neuropathologists, especially when the aid of advanced molecular and immunohistochemical tools is not available. Nonetheless, meticulous assessment of the morphological features with careful interpretation of the immunophenotypes can be rewarding often without the investment of an expensive molecular investigation. We propose a method of approaching the neuronal-glial tumors based on pattern recognition. We briefly discuss the key histological features that are helpful in narrowing down the differentials, with the aid of immunohistochemistry or available molecular information, directing the pathologist toward the correct diagnosis.